5:51 pm. That’s the moment on V-J Day in 1945 when a sailor planted his lips on a woman in New York City’s Times Square in one of the 20th century’s most famous photos, according to a study by astronomers from Texas State University and Iowa State University. And by finding the precise time, they might make it possible to disprove at least one claim about who was pictured in Alfred Eisenstaedt’s Life Magazine photo from the New York City celebration of allied victory over Japan in World War II.

The astronomers, in an article published in the August issue of Sky & Telescope, set out to show how much you can learn about a photograph by poking around in the shadows in its frame. The investigation actually began in the comment thread of a New York Times article in 2010 about the photo.

Steven D. Kawaler, one of the authors of Sky & Telescope article, got involved debating when the photo was taken. The clue that made this deeper inquiry possible, said Donald Olson, another author, was the shadow cast on a building in the top right corner of the photo.

“Every tall building in Manhattan acts like the gnomon of a sundial,” the authors explain in the article.

From the image, they could assess that the top of the shadow was 94 feet above the street on what was then the Loew’s Building at West 45th Street and Broadway.

By working out what structure caused the shadow, the scientists could compute the sun's position, and thus the time the photo was taken. With a topographical analysis of Manhattan’s layout at the time, they concluded that the shadow was cast by a sign atop the Hotel Astor and across the intersection from the Loew’s Building. By constructing a scale model of Manhattan and considering other details from accounts of the day, the sleuths arrived at 5:51 p.m. as the moment when the sun would have fallen at the correct angle to create the shadow on the Loew’s Building.

Dozens of people have claimed to be either the sailor or the nurse. But Mr. Eisenstaedt did not ask for the identity of the pair when he photographed them. One pair, George Mendonsa and Greta Zimmer, became the subject of a book, “The Kissing Sailor.” The book claimed to offer “irrefutable proof to identify the couple.” The Sky & Telescope analysis, pointing to their claims of meeting and kissing around 2 p.m., say that this analysis refutes the book’s account.

If not Mr. Mendonsa and Ms. Zimmer, who are the sailor and nurse? That’s a question that the astrophysicists can’t answer. Nor can looking at the shadows in the photo work out whether the kiss was consensual. But Dr. Olson was hopeful his techniques for investigating photos, paintings and other visual works of art had potential applications in other contexts.

“What we need to do it especially is a distinctive foreground, and then we can work with it,” he said by phone. “If you ask me to analyze a painting, I would look for distinctive buildings. When they paint anything with a distinctive feature, you can find it.”

Seabirds like albatross, petrels and penguins face a growing threat from plastic waste in parts of the Pacific, Atlantic, Indian and Southern Oceans, according to a new study published on Monday.

Brightly colored floating bits – debris that includes items such as discarded flip-flops, water bottles and popped balloons – often attract seabirds, which confuse them for food like krill or shrimp. Many die from swallowing the plastic.

The problem received some national attention in 2013 with the documentary “Midway,” which showed a remote island in the Pacific covered in corpses of baby albatross. Their exposed innards revealed lighters, bottle caps and toothbrushes mistakenly fed to them by their parents.

Researchers from Australia and Britain analyzed a number of papers from 1962 to 2012 that had surveyed 135 seabirds. The team found that fewer than 10 percent of seabirds had traces of plastic in their stomachs during the 1970s and 1980s. They estimated that today that number has increased to about 90 percent of seabirds. And they predict that 99 percent of all seabirds will swallow plastic in 2050.

For Erik Van Sebille, an oceanographer at Imperial College London and co-author of the paper, the most surprising findings from their analysis were the locations where seabirds were most likely to ingest plastic.

Researchers had previously thought that giant garbage patches swirling between Hawaii and California were the most likely places where birds would eat the waste. Instead, most seabirds are ingesting plastic at hotspots that stretch from Australia and New Zealand to South Africa and Chile.

Boris Worm, a marine biologist from Dalhousie University in Nova Scotia who was not involved in the research, said that seabird deaths are the most visible sign of a larger threat that plastics pose to marine wildlife like fish, whales and sea turtles.

“It’s an indicator that our world is literally getting clogged by plastic,” he said.

The study’s authors suggest stricter regulations on plastic production, consumption and disposal, as well as the development of plastics that degrade in seawater.

This polychaete worm, just under eight inches long, was found three miles down during the deepest dive ever made in the Papahānaumokuākea Marine National Monument, a conservation area in the Hawaiian Archipelago.

The Okeanos Explorer, a ship which belongs to the National Oceanic and Atmospheric Administration, is surveying the waters of the monument and other areas in the Northwest Hawaiian Islands and using a remotely operated vehicle e and other technology to map and document the life and environment of the deep ocean there.—JAMES GORMAN

This mouth-operated joystick called the Puffin is made for people who can’t use their arms or hands. It allows them to check email, send texts and post the selfie they just took to Instagram. By manipulating the joystick with their mouths, users can maneuver a selector on a mobile device like a smartphone; a “simple pressure system” capable of detecting both length and intensity registers sharp inhalations and exhalations as input — accomplishing the same thing as a person using his or her fingers to tap out a text.

The sip-and-puff technology underlying the Puffin — which requires users to suck air out of or blow air into a mouthpiece — has helped people with mobility impairments for more than 50 years. But it’s not enough to be able to flick a light switch on or off in the era of smartphones.

“There’s nothing really for mobile devices, and that’s what this is really about,” said Adriana Mallozzi, an accessibility advocate who has cerebral palsy and consulted with four M.I.T. students who built the device. In Ms. Mallozzi’s experience, other sip-and-puff accommodations — nearly all of them intended for stationary use — are far too limiting.

“They’re very large and clunky and cost too much to travel with,” she said of similar devices, some of which can cost more than a thousand dollars. By contrast, the Puffin prototype was assembled from materials that cost less than $200 and was able to be configured to the precise specifications of Ms. Mallozzi’s powerchair.

Ms. Mallozzi and her team devised their Puffin prototype during a “hackathon” intended to spur innovation in assistive technologies. Other submissions included a motorized turntable to spread cream cheese on a bagel without the use of hands and a hands-free walker.—LOUIS LUCERO II

It’s a “Name That Tune”-type game with a twist, one that its creators hope to eventually use to help dementia patients. The game, a citizen science project called Hooked On Music, tests how quickly people can recognize snippets of the 200 top pop songs in Britain since the 1940s.

Last year, scientists in the Netherlands who created the game reported that, based on the recognition speed of about 12,000 people, the catchiest single was “Wannabe” by the Spice Girls. And the catchiest part? Not the “I’ll tell you what I want, what I really, really want” part or the “zigazig ah” part, but the “If you wanna be my lover” part. When the song started at that point, a typical player guessed it in 2.29 seconds.

“Mambo No. 5” was the second catchiest, with players recognizing it 2.48 seconds after Lou Bega sings the part about Monica, Erica, Rita and Tina. And “Eye of the Tiger” by Survivor was recognized in 2.62 seconds after players heard the subtle hint of the line, “It’s the eye of the tiger.”

John Ashley Burgoyne, a computational musicologist at the University of Amsterdam who created the game with colleagues, said their analysis found that three things made a song especially memorable: a repetitive melody (like the fourth catchiest song, Lady Gaga’s “Just Dance”), “melodic conventionality” (“SOS” by Abba – fifth), and a prominent vocal (Roy Orbison’s “Pretty Woman” – sixth).

But the researchers are not just interested in what makes a musical “hook.” Dr. Burgoyne, a Maine native who trained as a classical singer, wants to use it to find songs that can prompt memories for people with dementia. Often, dementia patients can recognize songs, especially from their youth, and playing familiar music can soothe them or stir other recollections. To gather data toward that goal, a new version of “Hooked on Music” was unveiled last week and will be featured this fall at Britain’s Manchester Science Festival, which is partly supporting the research. The new game “tunes itself to you,” Dr. Burgoyne said, by responding to participants’ guesses and sending them more songs like the ones they are better at recognizing.

To play, click yes the instant you recognize, say, “Macarena.” Then the track goes silent for 4 seconds, during which you’re supposed to hum or sing the tune out loud or to yourself. As in an earlier version, when the song returns, you’re asked if it picked up at the right spot or not. If you’re correct, you get credit for recognizing the song. The updated game deconstructs players’ skill at recognizing songs that emphasize melody, bass line or rhythm. People better at rhythm-centered music will eventually get two-thirds of their snippets from songs with strong rhythms, Dr. Burgoyne said.

“If we can get this model calibrated in a healthy population, then we can translate it to a dementia population,” he said. He says he envisions the program creating, with a caregiver’s help, a “list of songs that are going to be most recognizable for this patient.”

One other change in the new version: the playlist no longer includes the Beatles Symphony Orchestra. “People really didn’t like it,” Dr. Burgoyne said. “We got complaints.”—PAM BELLUCK

The recent eruption of the Galapagos Islands’ tallest volcano left Gabriel Gentile breathlessly waiting for news. How was the pinky, he wondered. Would spewing gases and ash endanger the last surviving pink iguanas, a species Dr. Gentile, an evolutionary zoologist, is largely responsible for putting on the biological map?

So far, the roughly 200 pink iguanas, which live only on the northern slope of Wolf volcano on Isabela Island, seem O.K. Maybe that’s to be expected of a species that’s clung to survival in exceedingly harsh terrain, is at least a million years old and has until recently evaded the gaze of humans.

Pink iguanas were first seen by park rangers in 1986, but were considered flukish rose-colored variants of the much more numerous yellow iguanas until Dr. Gentile and his colleagues determined otherwise in 2009. He said Conolophus marthae (named in memory of Martha, Dr. Gentile’s stillborn daughter) is genetically, morphologically and behaviorally different enough to be its own species, and is the earliest of the three Galapagos land iguana species to split from their reptilian ancestor.

How Wolf volcano, only about 350,000 years old, became their outpost is one of many mysteries. “We are talking about a very old lineage that occurs on one of the youngest islands of the archipelago,” said Dr. Gentile, whose home base is the University of Rome Tor Vergata.

The color of chewed bubblegum, spangled with some blackish stripes, pink iguanas are smaller than yellow ones and have different crests and different “nodding behavior.” They are threatened by nonnative feral cats and parasites, by limited genetic diversity, and by the fact that there are fewer females than males. Not all females are fertile, and those that are produce fewer eggs than yellow iguanas.

After Wolf’s eruption, rangers sent Dr. Gentile blood samples from five pink iguanas, which he will test for elevated levels of stress hormone. This year, he plans to outfit several iguanas with tiny GPS trackers to study them better.

One theory why so few remain is that “being pink may cause some damage,” he said, exposing them more dangerously to ultraviolet radiation. “I don’t think being pink is an advantage.”—PAM BELLUCK

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In 1989, an Argentine rancher found one of the biggest dinosaurs ever unearthed, the Argentinosaurus. He thought it was a piece of driftwood.Credit
Rickey Rogers/Reuters

We were kids. It was summer. And the shovels were bigger than our bodies. We carried the shovels to my backyard with naïve confidence and endless energy. My siblings and I were certain that our North Carolina backyard had once housed hundreds, probably thousands of dinosaurs. Every chance we had, we dug. And when we didn’t find anything, we dug deeper. Our excavations resulted in quartz crystals and a moratorium on digging after my father drove his riding lawn mower into a hole for the umpteenth time.

We never found a single bone, which makes sense. In the United States, some of the areas where paleontologists have had the most luck finding dinosaurs are eastern Montana, western North Dakota, northern Wyoming and northeastern New Mexico. In April a 5-year-old helped dig up a dinosaur behind a grocery store in Texas. And Utah’s Grand Staircase-Escalante National Monument has been the site of thousands of dinosaur fossils, including a tyrannosaur found last summer. Except for the aetosaur, a prehistoric reptile that is not technically a dinosaur, bone remnants of the ancient creatures have not been found in North Carolina.

They’re not in Illinois either, where Stephen L. Brusatte, now a paleontologist at University of Edinburgh, spent his childhood digging for bones. Dr. Brusatte has uncovered dinosaurs in Portugal, Poland, Romania, New Mexico and most recently China, where he was part of a team that dug up a winged cousin of the velociraptor. On behalf of all dino-crazed kids out there, I asked Brusatte for tips.

Dinosaurs are always in fossilized rocks, so first find the right rocks. The “right” rocks were formed where dinosaurs lived – in rivers, lakes or sand dunes – 230 million to 66 million years ago during the Mesozoic era. The Smithsonian National Museum of Natural History and the United States Geological Survey provides maps and papers that describe these rocks and their locations. But if you’re willing to settle for less than a dinosaur, The Fossil Guy offers some suggested locations.

Leave that fancy radar you saw in “Jurassic Park” at home. Once you’ve picked a spot, “it’s down to patience, perseverance, good eyesight and plain old good luck,” Dr. Brusatte said.

The magical spot is likely where others have found hints of dinosaurs, but no one ever looked carefully, he said. Geologists’ field notes can sometimes be “treasure maps” for dino bones. In 2009, a German geology student’s notes from a mapping project led Dr. Brusatte and his colleagues to “a mass graveyard of car-size amphibians” in the Algarve of Portugal.—JOANNA KLEIN

In the unlikely occasion that you do find a dinosaur bone or a comparably intriguing fossil, we expect you to send us a photograph of your treasure at summerofscience@nytimes.com or tag it #nytscience on Instagram.

An earlier version of this post misstated the group of scientists who study dinosaurs. They are paleontologists, not archaeologists.

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A different century-old message in a bottle that was recovered from the North Sea.Credit
MBA Archive

Marianne Winkler, a retired post office worker, discovered a peculiar bottle in April while vacationing with her husband on Amrum Island in Germany.

Inside the dusty glass tube was a piece of paper with the words “Break the bottle,” inscribed in bold red type according to The Telegraph.

When Ms. Winkler opened it, she discovered that the tiny bottle was a remnant of an ocean experiment conducted more than a hundred years ago. The message included a return address for George Parker Bidder from the Marine Biological Association in Britain.

From 1904 to 1906, Mr. Bidder performed an experiment to observe ocean currents, according to the association. The message found by Ms. Winkler was one of 1,020 weighted “bottom bottles” that Mr. Bidder scattered across the southern part of the North Sea, which borders Britain, Germany, the Netherlands and Scandinavia. Mr. Bidder planned to investigate how currents moved in the depths of the sea.

People who reeled up the bottles were enticed to record their location and return the information to Mr. Bidder for a reward of one shilling. More than half of his weighted bottles found their way back within four years. But a few hundred are still missing, possibly adrift in the ocean.

“We think this bottle was one of the last batch he sent out, in 1906, so that would make it 108 years old,” Guy Baker, from the Marine Biological Association told The Telegraph. If true, such an estimate would make Ms. Winkler’s find the oldest message in a bottle ever recovered, dethroning a 99-year old artifact released in 1914 and found in 2013.

In keeping with Mr. Bidder’s promise, the association rewarded Ms. Winkler’s historic find with a shilling.—NICHOLAS ST. FLEUR

The scientist who took these photographs calls himself a “bee hairdresser.”

It’s not enough to put an insect under a microscope and snap away. He has found that it’s necessary to comb it and flick away bits of dust or pollen that might prevent an observer from seeing facets that could be crucial to distinguishing one bee species from another. Depending on how old his deceased specimen is, he might need to rehydrate it.

But Sam Droege doesn’t mind working with such a select clientele. The biologist, who heads the Native Bee Inventory and Monitoring Program of the United States Geological Survey, says he has “artistic tendencies,” but it’s about more than making pretty pictures. He set out to improve upon the tools available to scientists who were trying to identify bees they found in the wild. And he took many of these photographs in the process, and subsequently posted them on what became a popular Flickr page.

“Bird watchers have it so easy,” he said of studying bees. “The number of species involved, we really know very, very little, and one reason is we can’t identify what they are.”

Many of the bees engage in behaviors one might not expect from creatures mainly thought of as sociable pollinators or honey-makers that might sting you. Take the Giant Resin Bee. This species from Asia doesn’t build its own nests. If it can’t find an abandoned one, it will seize a home from another species. It doesn’t fight fair, dumping resin it gathers on its victims so they can’t fly and fight back.

Another species, the polysocial hairy tongue, illustrates how many assumptions about bees can be confounded by nature. When it lives in warmer climates, it will congregate with other bees and live in groups. But when the species lives in colder, mountainous regions, Mr. Droege writes, it’s happy alone.

With bees facing manythreats, Mr. Droege says he wants people to better appreciate their diversity.

“Despite all our human cleverness, we still owe a lot to these bugs,” he says. “Look how beautiful they are!”—MICHAEL ROSTON

Want to make your own photographs of bees and other insects? Mr. Droege explains how in this tutorial.

To take this supersonic shot, NASA pilots flew a jet thousands of feet beneath a second airplane equipped with a high-speed camera. The second plane caught the moment that the jet exceeded Mach 1, the speed of sound.

By using special software, the researchers eliminated the desert background, enabling the usually invisible shock waves, vortices and engine plume to emerge. The researchers said that they hope these images will help them improve designs for future supersonic flights.—NICHOLAS ST. FLEUR

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A water droplet computer circuit. The design of the grid determines where the water droplets go and when they interact. Credit
Prakash Lab

Not one run on hydroelectric power. And not the kind of computer you use to post to Facebook or write email.

No. This is the simplest kind of computer, a machine that can perform logical actions because of built-in rules.

For instance, if "a" happens, then "c" happens. If "a" and "b" happen, then "c" must not happen.

In this computer a, b and c are movements of water droplets only microns in diameter. These droplets, which contain magnetic nanoparticles, zip around a minuscule grid that looks as if it is made of flat Lego pieces. The grid is magnetized, and its design creates the logical rules of movement for the droplets, which float in an oil film.

Manu Prakash and his colleagues at Stanford University built such a computer and are inviting designs for more.

The point of the construction, originally detailed in Nature Physics, is not to find a new way to solve math problems but to build a new way to move matter around. The water droplets can carry drugs or nanomaterials. According to the design of the computer, the droplets could sort themselves out, combine, even organize into structures. This kind of computer could lead to a new world of manufacturing.

His website is not for the faint of mind. But if you have the nerd cred, or simply the ambition to plunge into a new world (complete with tutorials), go for it.

There are tutorials. You can download software to design your own water computer. His team will post your design on their site.

And, if they like the design, they'll build it.—JAMES GORMAN

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Megan Leftwich with her students observing California sea lions at the Smithsonian National Zoo.Credit
William Atkins/The George Washington University

To Megan Leftwich, California sea lions are some of the ocean’s most fascinating acrobats.

While large fish swim by wiggling their tail fins from side to side, and many marine mammals move with exaggerated up-and-down strokes of their tails, sea lions swim by using the front flippers to thrust the body forward smoothly through the water.

This allows them to glide, spin and perform underwater barrel rolls, without creating much disturbance behind them. It’s a quality that makes them unparalleled stealth swimmers — and prime targets for researchers looking to make covert underwater robots.

Dr. Leftwich, who studies fluid dynamics at George Washington University, noticed this peculiar propulsion system one day while watching the marine mammals at the Smithsonian National Zoo in Washington. Intrigued by the mathematics behind this motion, she and her team set out to investigate what happens to the water as sea lions swim through it.

Over the course of two years they recorded more than a hundred hours of video so that they could deconstruct the movements of the sea lion's foreflippers frame by frame. The team also took high-resolution laser scans of a foreflipper from a sea lion carcass; they published that work this month in The Journal of Aero Aqua Bio-mechanisms.

Using the data and the 3-D computer models, they mapped individual points on the sea lion’s flipper onto a digital foreflipper, and then observed its motion in a simulation.

They then mathematically decoded how the sea lion moves: First the animal collects water in its foreflippers, and then quickly scoops the water in toward its body. Then it claps its flippers against its torso, pushing the water toward its rear flippers and propelling it forward in a glide.

“By generating thrust with their foreflippers in a jetlike motion, they are using a different paradigm of swimming from really any other type of swimmer,” Dr. Leftwich said. The only animal that comes close to doing what the sea lion does would be a human doing the breaststroke, according to Dr. Leftwich.

The team has used that information to 3-D print a robotic foreflipper in hopes of finding out more about the sea lion’s stealthy strokes.—NICHOLAS ST. FLEUR

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Credit
University of Sydney and National Information and Communications Technology Australia

This may look like the set of a Claymation video, but it is actually a still shot of a new digital map revealing the composition of our ocean floor. Based on this color bar, you can imagine what walking on the bottom of the ocean might be like — sandy, muddy, rocky and full of fragmented shells and corals.

Scientists at the University of Sydney’s School of Geosciences and National Information and Communications Technology Australia research center used around 15,000 samples of seafloor sediments to create the map. It’s one of the most notable records of our planet’s mysterious land beneath the sea since the cartographer Marie Tharpdrew her map by hand in the 1970s.

Before Ms. Tharp, many thought the ocean floor was just a relatively flat bed of mud. But together with her colleague, Bruce Heezen, Ms. Tharp discovered a rift in the mid-Atlantic Ridge and changed the theories of continental drift. Spinning today’s interactive map shows an ocean blanketed in clay (brown) and a layer of skeletal debris called calcareous ooze (light blue).

Scientists hope that the map of seafloor components, like remnants of once living sea creatures, will help them to better understand how climate change affects the ocean.—JOANNA KLEIN

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Data backs up the notion that many Americans are "skinny fat" and "healthy obese" — their body fat percentage tells a different story than their B.M.I.Credit
Source: National Health and Nutrition Examination Survey, 2005–2006

About 18 percent, says data from the Centers for Disease Control. As part of the National Health and Nutrition Examination Survey, the agency surveyed body fat levels of over 5,000 people across the country about 10 years ago. Along with measuring people’s height and weight, researchers used a special type of density-measuring X-ray called a DXA scan to measure body fat percentage.

As you can see in the graphics here, there was a strong relationship between B.M.I. and body fat percentage, but for almost one in five adults, the two measurements disagreed. Eleven percent who were overweight according to B.M.I. had normal body fat. They are potentially some of the “healthy obese.” More troubling, 31 percent who were of normal weight according to B.M.I. had excess body fat. They could be called “skinny fat.” Excess was considered to be a body fat percentage over 25 percent for men and over 35 percent for women. Women were more likely than men to be in the normal B.M.I. range but have high levels of body fat.

B.M.I. is commonly used to classify people as overweight or obese because its components, height and weight, are much easier to directly measure than body fat percentage. Affordable and convenient methods of measuring body fat are inaccurate, and more precise tools like a DXA scan are expensive and inconvenient.

The consequence is that some perfectly healthy high-B.M.I. people might be unnecessarily worried about their weight or penalized by higher insurance premiums. And some normal-B.M.I. people may be fatter than they realize and facing the same health risks as the obese. – ALBERT SUN

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“If the vultures continue to disappear, can you imagine? This whole beautiful place will become one stink pit.”

Though they are millions to billions of times the mass of our sun and gobble every stray star, planet and wisp of dust that wanders by, supermassive black holes are rather shy types.

They are thought to exist in most if not all large galaxies, but they typically hide behind clouds of gas and dust, hampering efforts to better understand them.

This summer, however, a group of astronomers at Durham University in England reported that they had used NASA’s Nuclear Spectroscopic Telescope Array, or NuSTAR, to detect five supermassive black holes rapidly engulfing matter at the center of their galaxies. Although the team had hypothesized that there were undetected black holes existing in particularly dark and dusty galaxies within our universe, the proof was nonexistent — until NuSTAR came along.

Launched in 2012 and controlled by NASA’s Jet Propulsion Laboratory in California, NuSTAR is an orbiting telescope with the ability to detect the highest-energy X-rays emitted by active black holes – including ones hidden by dust so thick that previous satellite observatories could not cut through. The team pointed the telescope at these nine galaxies suspected of harboring black holes based on previous observations from other telescopes. NuSTAR confirmed that five of them indeed housed active black holes at their centers. The team speculates that black holes in the other four are hidden even deeper behind gas and dust.

Their finding lends support to the notion that the universe may contain millions of supermassive black holes that are hidden from view.

The astronomers, led by George Lansbury, presented their findings at the Royal Astronomical Society’s national meeting last month in Wales. The Astrophysics Journal has accepted their paper for publication.

In its three years of operation, NuStar has proven to be a game changer in black hole research, Dr. Lansbury said by email. "The next stage would be to hunt for more of these hidden black holes," he said. And sure enough, his team is currently "exploring new ways to select target galaxies for NuSTAR.”

The future of black holes is bright, friends.—ASHAKI LLOYD

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A large intact fossil specimen of an early aquatic plant, Montsechia.Credit
David Dilcher

More than 300 million years later, there were no flowers. Dinosaurs were walking the Earth before the blooms of the first flowering plants appeared, probably 140 million to 150 million years ago.

Scientists have yet to find fossils of the first flowers. (Without hard pieces like shells and bones, plants are less likely than animals to be preserved.)

But now paleobiologists have Montsechia, which lived at least 125 million years ago, putting it in the running for the oldest known flower.

It is an odd flower, because it lived fully submerged in water. The evolutionary innovation of flowers was that colorful petals attracted insects to spread the pollen, and pollinating insects do not swim.

But Montsechia used water currents rather than insects to spread its pollen.

"Now we see that extremely early in the evolution of flowering plants, they moved into the water, even before we have good records of more complex type flowers," said David L. Dilcher, an emeritus professor of geological sciences at Indiana University and an author of a new paper describing Montsechia published last week in Proceedings of the National Academy of Sciences.

The species itself is not a recent discovery, first unearthed in limestones in Spain more than a century ago, and biologists have tussled for decades over what kind of plant it is.

Over the past decade and a half, scientists led by Bernard Gomez of the Claude Bernard University Lyon 1 in France collected hundreds of specimens, painstakingly dissolving away the surrounding rock with hydrochloric acid, drop by drop.

That enabled them to identify fruits — the defining characteristic of flowering plants, or more technically, angiosperms.

Some drivers cruise California’s Interstate 280 for scenic views of rolling hills, a pristine reservoir and the San Francisco Bay. But for Kathryn Harrold, it's the gruesome sights on the side of the road that catch her eye: squished squirrels, raccoon carcasses, opossums pulverized into the pavement.

Ms. Harrold, who works as a marketing manager for a real estate agency near the I-280, spends some mornings and evenings before and after work volunteering with the California Roadkill Observation System, a project that documents dead animals struck by vehicles along the state's highways.

Whenever she spots roadkill, she pulls over to the shoulder, throws on her bright orange safety vest and steps out of her car. Then she snaps a picture in hopes that the grisly photo will eventually help prevent similar incidents.

“The animals are literally split into different pieces and torn in half all over the road,” Ms. Harrold said. “The blood splatters are morbidly breathtaking. It’s awful.”

There are more than 1,000 wildlife-vehicle accidents reported each year according to the California Department of Transportation and the California Highway Patrol statistics. Since 1994, at least 110 of them have been fatal for humans as well.

With about 3,600 entries, raccoons top the road kill list, followed by skunks and deer. Bears, coyotes and mountain lions, though less frequent, also appear in the website's galleries. Volunteers correctly identified an animal's species with 95 to 97 percent accuracy according to Dr. Shilling.

“We’re not just an accounting program for the death of animals,” Dr. Shilling said. “We’re providing a tool so people can participate in the conservation of wildlife and nature.”

Earlier this year the organization used the database to construct an interactive map that shows roadkill “hot spots”along the state's highways. They hope the information will help the state identify where to install fencing or culverts that provide wildlife with safe crossing alternatives.—NICHOLAS ST. FLEUR

Looking from the window seat on a long plane flight, you might have noticed that large swaths of the United States are divided into a latticework of farms, towns and forests. The cells of that grid, each one mile to a side, are the visible result of a land planning system first proposed by Thomas Jefferson more than two centuries ago.

The images here, taken from the Instagram account @the.jefferson.grid show just a few of the landscapes that can be squeezed into the one-mile squares. The account's curator, who prefers to remain anonymous, uses Google Earth to find interesting blocks across the country.

Forests, the boundaries of small towns, and farmer’s center-pivot irrigation systems all submit to the grid’s relentless logic. Thin gray and white streets trace the squares, often signaling where one property ends and another begins.

The idea behind this sprawling checkerboard emerged after the Revolutionary War. As the United States expanded westward, the country needed a systematic way to divide its newly acquired lands. The original colonies were surveyed using the British system of “metes and bounds,” with parcels delineated using local geography and cataloged with riveting language:

“Beginning at corner No. 1, a hemlock post, 4 in. square, 24 in. above ground, located on the Takotna Highway about 1/4 mile southeasterly from its intersection with the left bank of Kuskokwim River…”

That approach doesn’t scale very well, and Jefferson, an ambitious politician who would become president about two decades later, was made chairman of a committee to find an alternative. He proposed to slice the young United States into gridded plots of land that would support his ideal country of “yeoman farmers” who would form the backbone of American democracy.

Jefferson's idea became a reality in 1785 when it was enacted as the Public Land Survey System. Today his grid covers much of the country, and it is still used to survey federal lands — an idea that shaped the physical landscape of half a continent.—DEREK WATKINS

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An artist's conception of the asteroid impact 65 million years ago that is believed to have killed off the dinosaurs.Credit
Don Davis/NASA

As the apocalypse story has it, the asteroid impact would occur between Sept. 15 and Sept. 28 near Puerto Rico.

In the NASA release, Paul Chodas, manager of the Near-Earth Object office at the Jet Propulsion Laboratory in Pasadena, Calif., said, “There is no scientific basis — not one shred of evidence — that an asteroid or any other celestial object will impact Earth on those dates.”

The danger of a collision with any of the known asteroids over the next century is less than one in 10,000, the space agency said.

This is not the first time a story of impending doom from outer space has circulated on the Internet, but this one persisted long enough to garner NASA attention.

“We’ve still been getting calls and getting emails, and September is coming up,” said D. C. Agle, a spokesman at the Jet Propulsion Laboratory. “Some of these things just have a life of their own, so it seemed like a good idea to put out a release.”

Scott Kelly, a NASA astronaut, captured a spectacular video of the aurora borealis this weekend as the magnificent blends of blues, greens and purples danced across the sky.

The light display appears when plasma particles blown from the sun collide with Earth's magnetic field. The clash causes the solar particles to excite oxygen and nitrogen atoms in the atmosphere and emit dazzling light.

Mr. Kelly took the images from the International Space Station, some 249 miles above the planet, while buzzing by at approximately 17,000 miles per hour. The new video comes on day 141 of his year-long mission on the International Space Station. It's just one eye-catching entry in his diary of tweets.

No word yet if he enjoyed the view while snacking on a side of space salad.—NICHOLAS ST. FLEUR

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The vomit machine.Credit
Grace Thompson/North Carolina State University

Spontaneous beach days aside, one of the most likely reasons your coworker contracted the elusive “24-hour bug” was because she caught a stomach virus known as the norovirus.

According to the Centers for Disease Control and Prevention, more than 20 million Americans catch norovirus every year. And of those who become sick, only about 5 million get infected from eating contaminated food, according to Dr. Lee-Ann Jaykus from North Carolina State University. The majority of cases, she said, come from people catching the virus from other infected people.

Since vomiting — particularly projectile vomiting — is a hallmark symptom of a norovirus infection, Dr. Jaykus decided to investigate how vomit could spread the disease. She suspected that after someone throws up, virus particles could be aerosolized, or released into the air.

In order to demonstrate that in the lab, Dr. Jaykus and her team constructed their own “vomit machine” made out of tubes, pumps and valves with a clay face.

They loaded the machine’s “stomach” with fake vomit, and added pudding to make it chunky. Then they mixed in a virus called MS2, which is similar to norovirus but much less dangerous. The machine was locked into a Plexiglas chamber to puke its mechanical brains out.

While testing the machine the team turned to Youtube for insight into how people throwup.

“We scanned the Internet. You’d be amazed at how many vomiting incidents there are,” Dr. Jaykus said. One fact they found was that people tend to cough a few times after throwing up, a feature they added to one of their simulations.

Using a biosensor the researchers found that in all cases the vomit did spew viral particles into the air and that the amount of viral particles increased when the machine ejected with more pressure. The coughs also increased the amount of virus particles in the air. The team published their findings Wednesday in the journal PLOS One.

The experiment found that only 0.00007 percent to 0.03 percent of the vomit’s volume could be aerosolized, which translated to between approximately 40 and 10,000 virus particles.

Although that may seem infinitesimal, Dr. Jaykus said that those amounts are actually quite significant because it only takes between 20 and 1,300 norovirus particles to infect someone.

“That equates to a lot, a lot, a lot of potential illness that could arise from just that single vomiting event,” she said.—NICHOLAS ST. FLEUR

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This video was captured in Rhossili, a town in Wales.Credit
By THE ASSOCIATED PRESS

Wednesday night’s Perseid meteor shower offered a spectacular light display. If you missed the show, Thursday and Friday's should be similarly stellar. And while you should feel free to call them shooting stars, just remember that's not what they truly are.

Dennis Overbye described a meteor shower this way in 2002: "As the Earth plows into that cloud, crumbs of matter left behind by the comet scream into the atmosphere and die a breathtaking death."

Earlier this week Summer of Science offered a short guide to Perseid meteor shower, which coincides with the new moon on Friday. Andy Newman also offered watching tips specifically for New Yorkers.

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An Allonautilus scrobiculatus with a radio transmitter, left and in the left hand of Chief Peter in Ndrova Island, Papua New Guinea. Credit
Peter Ward

This is an Allonautilus scrobiculatus, a rare cousin of the nautilus that was the namesake of Captain Nemo’s submarine in “Twenty Thousand Leagues Under the Sea.” Earlier this summer it and three of its friends had radio transmitters epoxied to their shells so that a group of researchers could follow the little critters as they migrated between Ndrova and Manus, a pair of islands in Papua New Guinea.

Peter Ward, a paleontologist at the University of Washington and the leader of the team, discovered the allonautilus back in 1984 with his colleague Bruce Saunders. Though it may resemble the better known chambered nautilus worn on necklaces, it was so different in shell and soft part anatomy that it was eventually proclaimed not just a new species, but a wholly new genus: Allonautilus.

But then several decades passed without a definitive sighting and Dr. Saunders began to fear that Allonautilus had gone extinct.

When Dr. Ward returned to Papua New Guinea this summer, he found they are still there — but not all that easy to track. He and his crew of helpers spent the summer trying to stay above the nautilus in a canoe because the radio transmitter on its back only had a range of about 3,000 feet. As a result the Allonautilus, which inhabits depths of 300 to 1,000 feet, kept giving them the slip, Dr. Ward complained.

“I have all the appreciation possible for submarine hunters sitting in ships above,” he wrote in an email.

But his concerns about the fate of the Allonautilus persist.

“The possible bad news,” Dr. Ward reported by email, “is that their habitat, this part of Papua New Guinea where uniquely in the world two genera of nautiloid cephalopods live, is slated soon for large scale deep water mining that will dredge the seafloor, a seafloor above which these ancient survivors still live. But for how long?”—DENNIS OVERBYE

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Humans, like this bear preying on salmon in coastal British Columbia, are predators.Credit
Andrew S. Wright

We hunt not just lions and tigers, but also bears, wolves, deer and elk. We fish tuna, seabass, swordfish and salmon. We kill for food and sport.

But here’s a “what if?”: What if humans were considered as just another predator within the global ecosystem, rather than apart from it? How do our predatory habits compare with those of other top carnivores like lions, bears and sharks?

Those are the questions that Chris Darimont, a conservation scientist at the University of Victoria in British Columbia, set out to investigate. He and his colleagues wanted to put global hunting into context and quantify the impact of human predation.

The team combed through more than 300 research papers and constructed a database with more than 2,000 instances of human and nonhuman hunting and fishing. The biggest difference they found is that humans overwhelmingly kill adult prey while carnivores tend to hunt juveniles, for the simple reason that they are easier to kill.

This could be because humans prefer large trophies. “You will not hear a fisherman brag about the smallest fish of the day,” Dr. Darimont said.

The team also reported that commercial fisheries caught adult fish like cod and tuna at 14 times the rate that natural marine predators did. On land, humans and animal predators hunted herbivores like moose and deer at similar rates, but people killed large predators like bears and wolves at nine times the rate that these carnivores killed each other.

Dr. Darimont and his colleagues concluded that humans are “super predators” that hunt prey at unsustainable rates. They published their research Thursday in the journal Science.—NICHOLAS ST. FLEUR

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“This is the biggest breakthrough for women’s sexual health since the pill.”

—

Sally Greenberg, executive director of the National Consumers League, on the F.D.A.'s approval of Addyi, a libido drug for women.

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“I’ve learned that humanity is not as bad as we think.”

—

Zod Arifai, a chef in Montclair, N.J., who let diners at his restaurants pay what they want.

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Two men arrange to meet at a cafe and exchange other pleasantries by whistling across a valley about 765 yards wide in Kuşköy, Turkey.Credit
ONUR GÜNTÜRKÜN

Unlike all other spoken languages, a whistled form of Turkish requires that “speakers” rely as heavily on the right side of their brains as on the left side, researchers have found.

Whistling requires adjustments in frequency, pitch and melody, all tasks handled by the brain’s right hemisphere, said Onur Güntürkün, a neuroscientist at Ruhr-University Bochum in Germany and an author of the study. He and his colleagues reported their findings in the journal Current Biology.

Whistled Turkish is used to communicate over long distances in the mountainous terrain of northeastern Turkey. Dr. Güntürkün administered a standard listening test to subjects who rely on whistling. Different speech sounds were delivered simultaneously to the right and left ears of each subject.

When listening to fragments of spoken Turkish, the subjects more often heard the sounds played to the right ear. That’s because the brain’s left hemisphere receives input from the body’s right side and processes speech, Dr. Güntürkün said.

But the subjects picked up whistled Turkish equally well in either ear. “The pattern of 50-50 tells us that indeed the physical format of a language alters the way the brain processes it,” Dr. Güntürkün said.

The whistled language may be used by 10,000 to 50,000 people today, said Dr. Güntürkün, a native speaker of Turkish.—SINDYA N. BHANOO

Walk into any marijuana dispensary in California or Washington State, and prepare to be overwhelmed by the choices. Growers have cultivated hundreds of strains, and retailers often sell dozens purporting to have particular medical or recreational properties.

In truth, scientists are still struggling to understand how marijuana affects individual users, as this video explains. The main psychoactive ingredient, THC, induces the “high” experienced by users, but other chemical compounds in the plant may influence it, a phenomenon some experts call “the entourage effect.”

As a result of this factor and several others, it’s difficult to predict a particular strain’s effect on a particular individual — but that probably won't stop the marketing efforts in the growing marijuana industry.—AXEL GERDAU

Off the coast of Angola, an unmanned submarine patrolling a BP oil well some 4,000 feet down recently recorded video of this guy lurking along the sea floor. Up on the surface, the BP team nicknamed it a “Flying Spaghetti Monster.”

To find out its real name, they turned to the Serpent Project, a group of marine biologists that works with the oil industry to explore the deep sea and conduct environmental assessments. The companies use video and photography to quickly scout large swaths of the sea floor, and intriguing creatures are sometime caught on camera in the process.

Daniel Jones, a marine biologist, was the first on Serpent’s team to receive the video. At first, he said, “we weren’t sure what kind of species it was.”

The Serpent team, with the help of a colleague, Phillip Pugh, concluded it was a Bathyphysa conifer. (That is pronounced bath-ee-fye-sah kohn-iff-er — like the trees — according to the American Museum of Natural History.)

Bathyphysa conifer is very closely related to the Portuguese Man O'War, and shares its venomous sting. Similarly, it pulses its body to move around in the water, but it does not have the strength to swim against ocean currents.

According to Dr. Jones, Bathyphysa conifer was first described in 1878 after German trawlers snared one in their net. They are believed to live in both the Atlantic and Pacific Ocean, but since they live at great depths they are rarely seen. When they are brought to the surface, they’re often in tatters because their bodies are very fragile.

Similar to corals and sponges, this Bathyphysa conifer is actually a whole colony of different individuals. In the video, you can see a large bulb at the top of the creature, which acts as a float. Just below it is a series of thick, relatively stubby feeding structures. These are just "developing" but further down, there's a skirt of longer, more mature feeding structures with thin stinging tentacles that are used to catch prey. Each feeding structure is a member of the colony and they all have to be clustered together for the Bathyphysa to survive.—EMILY HAGER

Buried in a smush of stars known as RGG 118 — and noticeable only by a plaintive squeal of X-ray radiation — astronomers have discovered a new black hole. By the standards of normal life it’s not so small, a pit in space-time 200,000 miles across into which the equivalent of 50,000 suns have disappeared. But on a cosmic scale it’s not so big.

Almost every galaxy, like the Milky Way, has a supermassive black hole millions or billions of times as massive as the sun sitting at it center. The bigger the galaxy, the more massive the black monster at its heart. Nobody knows why.

The new black hole is the first one found in a dwarf galaxy. RGG 118, as it is elegantly named, is 340 million light-years away and about a hundredth the mass of our own Milky Way, whose central black hole weighs some 4 million suns.

A team from the University of Michigan and Princeton, led by Vivienne Baldassarre, a Michigan graduate student, found and measured it by using NASA’s Chandra X-Ray Observatory and an optical telescope in Chile to chart the speeds of stars and gas swirling around in the small galaxy.

Observing the behavior of such a teensy, so to speak, black hole, Ms. Baldassare and her colleagues hope, will help them understand where the monstrous black holes found in regular galaxies come from and how they grow so big. Some astronomers speculate that they are seeded from giant clouds of primordial gas, or the collapse of gargantuan stars that inhabited the dawn of time, and then grew by merging with other black holes as galaxies collided during the rough and tumble days of the early universe.

The RGG 118 black hole is like finding a preteenager on the verge of all this. In the fullness of cosmic time, it could grow into a true monster.—DENNIS OVERBYE

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“I used the gorilla training method. Now my kids are really good at brushing.’’

What you are looking at is actually a combination of two devices, assembled into an imaging system developed by Professor Elisa Konofagou and her team. The orange face in the center is an imaging probe and the outer ring, studded with exactly 93 small, circular elements (I counted), is a transducer. That second component — a high-intensity focused ultrasound phased array transducer, if we’re being technical — could one day assist in the elimination of tumors without surgery. Developing those capabilities would be a particular boon for cancer patients who have tumors that were judged too risky for surgical intervention because of where they are located. Another welcome side-effect: reducing the need for radiation.

Like all ultrasound technology, this device uses targeted sound waves to generate an image. But unlike other uses of ultrasound, this tool could help doctors assess the elasticity of body tissues. In this approach, called harmonic motion imaging, tissue is probed with pulses of acoustic energy that are slightly greater than standard ultrasound and observed for its physical response.

Because cancer tissue is known to be, on average, stiffer than healthy tissue, any discrepancies between the observed and expected elasticity that are identified through the imaging process can indicate the presence of a tumor.

According to Yang Han, a Ph.D. student with the group, using a 93-element transducer instead of a more common single-element transducer allows researchers to direct the beam of ultrasonic energy, providing greater control when targeting tissues.

Although the array is currently being used only for research, the team sees an opportunity for therapeutic applications down the road. As Professor Konofagou explained in an interview with Columbia Engineering magazine, the same basic technology used to image tumors might be able to destroy them — no scalpel required.

“Exactly the same transducer, exactly the same system, generates thermal effects in the tissue, so it can burn the tissue at higher intensities,” she said. “Noninvasively, remotely, where you need it.”—LOUIS LUCERO II

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“They were convinced that no one would ever want to look at their pictures on a television set.”

As Comet 67P/Churyumov-Gerasimenko orbited closer to the sun, a fireworks show erupted from its surface. The images here, which were released Tuesday, show the brightest outburst captured so far, according to European Space Agency scientists.

ESA astronomers estimate that the stream of particles spurted from the comet's neck at 33 feet per second. The pictures were captured by the ESA's Rosetta spacecraft on July 29 as it orbited about 116 miles away from the comet, according to NASA.

You can see previous images from Rosetta's year around a warming comet here.—NICHOLAS ST. FLEUR

The larger Pacific striped octopus is, despite its name, no bigger than a tangerine. And it has long managed to keep a low profile in the coastal waters off the eastern Pacific.

It has appeared only once in scientific journals, and only as a brief mention. In 1982, Arcadio Rodaniche, a marine biologist and illustrator, wrote about behaviors that were unheard-of among octopuses, including intimate “beak to beak” mating. His surprising findings were dismissed by other scientists.

But now, more than 30 years later, Mr. Rodaniche’s findings about the the larger Pacific striped octopus are gaining newfound credibility.

Roy Caldwell, a researcher of invertebrate studies at the University of California, Berkeley, and his team obtained 24 of these octopuses from private collectors in Nicaragua and have just published their research in the journal PLOS One.

The species is indeed unusual. While other octopuses mate by mounting, the larger Pacific striped octopus engages in “beak to beak” mating, a much closer act, as the beaks are on the underside of their bodies. Females of the species have also been found to brood over their eggs for up to six months, far longer than females of other species of octopus.

They also appear to be surprisingly social creatures. The 24 octopuses that Dr. Caldwell studied were placed in groups of eight in large tanks. None of them killed any of their tankmates (octopuses are no strangers to cannibalism), and by all appearances they seemed to get along. Male and female mates even shared a den for up to three days.

The larger Pacific striped octopus also uses a “slow bounce” to hunt. With its body flattened, and dorsal arms reaching forward, the octopus glides with sporadic bursts of hopping movements before it snatches up its prey of choice — usually shrimp. For Dr. Caldwell, the movement reminded him of a “tiger stalking a prey.”—ASHAKI LLOYD

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John L. Phillips, a NASA astronaut, talked to students in Australia via the ham radio on the International Space Station in 2005.Credit
NASA

"It’s not very unusual," said Kyle Herring, a spokesman at NASA's Johnson Space Center in Houston.

It is not that people are breaking into the radio communications between the space station and mission control. "It wouldn’t be on the space-to-ground system we use," Mr. Herring said.

Rather, there is a ham radio on the space station like the ones used by amateur radio enthusiasts around the world. It is how space station astronauts conduct Q&A sessions with students, for instance.

The space station's ham radio frequencies are publicly available and you too can try to call the space station when it passes 250 miles above. (That is, if you have the proper equipment and required radio license.)

That does not mean anyone will answer, but sometimes one of the astronauts will be there and will converse. Of the two NASA astronauts currently on the space station, Kjell N. Lindgren, who joined the crew last month, does have a ham radio license while Scott J. Kelly, in the middle of a one-year stay, does not.—KENNETH CHANG

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“I am on the side of eliminating a species that is not a native part of this island’s environment.”

The images on the right from top; what a flower looks like to a bee; a lizard to fellow lizards; dandelions to a honeybee; a lesser Celandine to a honeybee. In each pair, the view that a human sees is presented on the left.

Honeybees buzzing in a garden view the world much differently than we do. What may seem like beautiful purple flowers to us appear to the insects as bright ultraviolet signs saying "We're Open."

That's because although both human and honeybee eyes have three-color receptors called cones, human eyes are sensitive to blue, green and red light, while honeybee eyes are sensitive to blue, green and ultraviolet light.

Eyes with different types of cones observe different parts of the light spectrum. So peacocks (which have four cones), ferrets (which have two) and some dogfish (which have none) all see the world a bit differently.

Researchers at the University of Exeter in Britain have now created a tool that transforms digital photos into what they are calling “animal vision,” allowing researchers to view images as they would be seen by a honeybee, peacock, ferret or other type of animal.

By applying special filters to certain images, the software can imitate the different types of light that specific animals in their data set see.

In the case of the flowers, the software illuminates the UV light that bees observe but is undetectable to the human eye. The authors said they think their tool will help biologists better understand visual signals from animals and plants.

A report about the tool, which is free to download but requires certain image processing programs to use, was published in the journal Methods in Ecology and Evolution last Thursday.—NICHOLAS ST. FLEUR

This week take a little drive to the beach, a field, or anywhere dark with a clear view. Bring a blanket and a pocket full of wishes, because the annual Perseid meteor shower will fill the sky with shooting stars. At its peak, between Aug. 11 and Aug. 14, an average of one shooting star a minute will zip through the night sky.

Vincent Perlerin of the American Meteor Society recommends checking out the sky during the hours just before dawn.

It may appear as if stars are darting at you from all directions. But trace each meteor backward, and you’ll see that all the lines come radially from the constellation Perseus.

The higher this constellation is in your sky, the better your view, says astronomer Jackie Faherty of the American Museum of Natural History. That means that the northeastern United States and other places with mid-northern latitudes close to 45 degrees, where Perseus is, will get a particularly good view, she says.

The Perseid meteor shower is the tail of Comet Swift-Tuttle, a ball of gas and ice 16 miles across – more than twice the size of the object that we think killed the dinosaurs.

“You definitely don’t want to see the source of your beautiful meteor shower,” said Dr. Faherty.

Although we call them shooting stars, the meteors we see flying through the sky are actually dust-sized particles of debris burning up in Earth’s atmosphere. Meteor showers result when Earth passes through the orbit of a comet – such as Swift-Tuttle – or an asteroid.

“A moon will ruin it for you,” says Dr. Faherty. But you’re in luck because this year the peak coincides with the new moon of Aug. 14. That means that the best night to point your pupils at the sky is Thursday, Aug. 13 – you’ll get the most showers with the least moonlight to outshine them.—JOANNA KLEIN

The left-handed, a minority among humans with few advantages unless they can throw a baseball or a punch, have just gotten some reinforcements from the far reaches of the animal kingdom. Scientists have discovered that red kangaroos are mostly southpaws. So are eastern gray kangaroos, and red-necked wallabies to a lesser extent.

But it's not the lefty dominance that is important to science. For the Russian and Australian scientists who reported their findings Thursday in Current Biology, the big news is that kangaroos show quite clear hand, or paw, dominance. Humans were thought to be the only mammals with strong, consistent handedness, although apes show some dominance on one side.

Andre Giljov and Yego Malaschichev at St. Petersburg State University, along with other researchers, thought it might be a good idea to go beyond primates to look at marsupials, the mammals that keep their babies in pouches, like kangaroos and opossums.

What attracted them to kangaroos is that some of them stand on two legs, and can use their forelimbs for manipulating objects, while others use all four legs to move. And it turned out that bipedalism was the telling factor in which kangaroos showed the lefty dominance. Tree-dwelling kangaroos who move on all fours did not show a strong bias.

That, said Dr. Malaschichev, is evidence that a bipedal life drives the evolution of left- or right-handedness.

Why left rather than right? That's still a mystery. But if kangaroos do start to play baseball, the influx of southpaws could drive managers crazy.—JAMES GORMAN

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“There’s only two places on the earth where wildlife at a large scale has actually increased in the 20th century, and those are North America and southern Africa. Both of those models of conservation were built around hunting.”

This series of images showing the moon passing over the Pacific Ocean near North America was taken by the Deep Space Climate Observatory between 3:50 p.m. and 8:45 p.m. Eastern time on July 16.Credit
NASA

Last week, NASA released a glorious animated GIF of the moon passing in front of the Earth that looked like a bad Photoshop cut-and-paste. (The colors do not even line up right.)

The Deep Space Climate Observatory, the spacecraft to which the pictures were credited, is located at the L1 Lagrangian Point, a fancy name for the point in space nearly a million miles away where the gravitational pull of the sun and of the Earth essentially cancel out. But that would mean the sun was directly behind the spacecraft, and the shadow of the moon should have crossed Earth as it passed in front.

But there's no shadow — and such lighting incongruities are usually the smoking gun of manipulated images.

The spacecraft, called Dscovr for short, is not exactly at L1, but instead circles around it. (That makes sense, because there are four spacecraft at L1, and one would not want them to smash into one another.)

Adam Szabo, the NASA scientist in charge of Dscovr's Earth-facing camera, said via email, "As the small sliver of shadow at the right edge of the moon shows, Dscovr is about 5 degrees away from the sun-Earth line. Thus, when the moon is between Dscovr and Earth, it is not exactly between the sun and Earth, so no eclipse."

But imagine the amazing images Dscovr will capture during the next partial solar eclipse, on Sept. 13, and total solar eclipse, on March 9 next year.

(NASA explains that the mismatched colors are because of the movement of the moon. Each color image is a composite of three black-and-white pictures taken through three different color filters about 30 seconds apart, which is why you see a thin arc of green at the right side of the moon.)

By the way, the side of the moon seen in the animation is the far side, not the dark side. It is facing the sun, so therefore it would be bright — daytime, just like on the surface of the Earth. Just as on Earth, half of the moon is always in darkness — nighttime, in other words — but the far side is not continually dark.

Update: According to the NASA team, the partial solar eclipse on Sept. 13 will probably not provide much to see from Dscovr's position. "The moon will be completely outside the camera’s field of view," Stephen Cole, a NASA spokesman, said via email.

But the March 2016 total eclipse could be a cool sight indeed. "That’s iffy at this point because the spacecraft orbital dynamics are still getting settled," Mr. Cole said. "But if orbital mechanics work out just right, EPIC" — as NASA calls the Earth Polychromatic Imaging Camera aboard the spacecraft — "could capture the moon’s round shadow moving across the equator. The moon itself may also be in the field of view."—KENNETH CHANG

Q. If the planet were rid of all mosquitoes, would there be any negative environmental consequences?

A. It is impossible to know for sure, because so many varieties of mosquitoes fill so many environmental niches, feeding on and being fed on by such a variety of other creatures, and because many of these interactions have not been studied.

But it is only natural that people, pestered by itchy bites and bearing the brunt of mosquito-borne diseases, would hope the answer is no.

Many birds, bats, amphibians, fish, spiders and other insects feed on mosquitoes, but many mosquito-control specialists say they usually do not eat enough mosquitoes to control them, let alone to make the loss of mosquitoes crucial to whether the predators survive.

Send your questions to C. Claiborne Ray at questions@nytimes.com. Questions of general interest will be answered, but requests for medical advice cannot be honored and unpublished letters cannot be answered individually.

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The first salad grown by NASA astronauts on the International Space Station is ready to eat.Credit
NASA

Astronauts on the International Space Station just took their first bite of "space salad," according to NASA. The new leafy green, a variety of red romaine called “Outredgeous,” was grown and harvested entirely on the station under red, blue and green LEDs in a special greenhouse aptly named Veggie.

According to NASA, sustainable agricultural techniques like this may one day be used to feed astronauts on a trip to Mars.—NICHOLAS ST. FLEUR

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“Coca-Cola’s agenda here is very clear: Get these researchers to confuse the science and deflect attention from dietary intake.”

—

Marion Nestle, the author of the book “Soda Politics” and a professor of nutrition, food studies and public health at New York University, on a report that Coca-Cola funds scientists who shift blame for obesity away from diets.

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“It’s your home. Imagine you start eating and you see the wine in your glass going left to right.”

This week archaeologists, wildlife ecologists and other scientists on Twitter shared embarrassing moments from their field research using the hashtag #FieldWorkFail. Among the confessions were tales of elephants crushing trap cameras, paleontologists accidentally swallowing fossils, and one case where a researcher unintentionally glued herself to a crocodile.

Not all fieldwork mistakes are as amusing, but even the unfunny ones can be fortuitous. For Carlos Jared, a biologist from the Butantan Institute in São Paulo, Brazil, a mishap in the desert led to a new discovery.

Dr. Jared had been studying tree frogs in the cactus and thorn forests of northeastern Brazil for decades. But on one particular day he wanted to get his hands on Corythomantis greeningi, a frog with a helmet-shaped head covered in tiny spines.

“During collection, very soon I realized that when grasping them with the palm of the hand, they intensely move the head in a characteristic butting behavior,” Dr. Jared said in an email. Later he felt a sharp pain radiating through his arm, which he described as being far worse than the worst wasp sting imaginable. Dr. Jared was at least four hours away from any hospital, so he decided to tough it out in the desert. Five hours later, the excruciating pain subsided on its own.

It wasn’t until he examined the frogs under a microscope that he discovered that the spines on their upper lips were covered in poison glands. “It took me a long time to realize that the pain had a relationship with the intense and careless collection of these animals hitting the palm of my hands,” he said. When the frog head-butted him, it envenomed him too.

Researchers already knew that the frog secretes toxins from its skin, but the poisoned spines on the head had not been documented before. Dr. Jared and his colleagues found that the same spiny and bony head occurs in another frog species, Aparasphenodon brunoi, which lives in the Atlantic rain forests of South America. They decided to test how toxic the two frogs were in the lab by injecting the poisons into rodents. To their surprise, they found that in mice, A. brunoi's secretions were 25 times as lethal as a Brazilian pit viper's venom, and those of C. greeningi, the one that pricked Dr. Jared, were twice as lethal.

Although Dr. Jared did not tweet his fieldwork faux pas, he did mention it along with his findings in a paper published Thursday in the journal Current Biology.

This is the first time anyone has suggested that a frog can be venomous, according to Edmund Brodie, a biologist from Utah State University and co-author on the paper. Hundreds of species of frogs are poisonous, like the Amazon’s brightly colored poison dart frog. But to be classified as venomous, a creature must have a method by which it can inflict that poison into a victim. For these two frogs, flailing the head suffices.

“It all started because Carlos was out collecting them and got jabbed in the hand by one of them,” Dr. Brodie said. “This is how one makes those ‘Eureka’ discoveries!”—NICHOLAS ST. FLEUR

A gigantic glowing bubble in the constellation Hydra is actually a planetary nebula, a gas cloud formed from a dying star. A striking new picture of the so-called Southern Owl Nebula was captured by the European Southern Observatory’s Very Large Telescope in Chile. The orb has a diameter of almost four light-years. A planetary nebula lasts tens of thousands of years and then fades, leaving behind a stellar remnant that persists for about a billion years. The remnant then becomes a hot, dense white dwarf that cools over billions of years.—SINDYA N. BHANOO

An earlier version of this post misstated part of the name of the organization that runs the telescope. It is the European Southern Observatory, not the European Space Observatory.

The radioactive element plutonium gets its name from Pluto. So it is only fitting that a variation of the unstable metal, known as plutonium 238, would be at the heart of the New Horizons mission that flew past the former ninth planet last month.

This isotope releases energy in the form of heat as it decays. New Horizons transforms the heat energy into electricity capable of powering its voyage through the solar system.

After directing the spacecraft beyond the dwarf planet, that decaying heart was “beating, and beating well, and beating still,” said Jim Green, the director of the planetary science division at NASA headquarters, in a news conference after the flyby. “Radioisotope power enables us to move further out into the solar system, and it’s on a trajectory to leave.”

By now, New Horizons has gone about 15 million miles beyond Pluto, and is steadily beaming data from the flyby back to Earth.

The energy conversion takes place in the craft's 125-pound generator, called the General Purpose Heat Source-Radioisotope Thermoelectric Generator. New Horizons was stocked with 24 pounds of plutonium that produced about 240 watts of electricity when it left Earth in 2006, according to Ryan Bechtel, an engineer from the Department of Energy who works on space nuclear power. During the Pluto flyby the battery produced 202 watts, Mr. Bechtel said.

The power will continue to decrease as the metal decays, but there is enough of it to command the probe for another 20 years, according to Curt Niebur, a NASA program scientist on the New Horizons mission.

In that time the spacecraft will have traveled 5.6 billion miles past Pluto. Its plutonium heart will beat softer with every mile, until it decreases to the point where there is no longer enough to support the systems that operate the spacecraft and communicate with Earth, according to Dr. Niebur.

When that happens, the craft will continue combing through the cosmos at the same speed and in the same direction until something stops it, Dr. Niebur said. But if nothing in the vast emptiness of space impedes New Horizons' travels, then "it will just keep going, forever, all alone in the deep dark," he said.—NICHOLAS ST. FLEUR

Giant Galápagos tortoises, the world’s biggest, have had it rough. Thanks to pirates and whalers eating them and to non-native species like goats destroying their habitat, four of the 14 documented species are extinct. Most recently, the Pinta species vanished with the 2012 death of Lonesome George, after decades of attempts to get him to reproduce.

But the tortoises emerging from the crates above represent a milestone in tortoise restoration efforts. They are among 201 tortoises recently released onto Santa Fe Island, which lost its tortoise species a century and a half ago.

“We wanted to do this for a long time,” said Linda Cayot, the science adviser for the Galápagos Conservancy, which, in collaboration with the Galapagos National Park Directorate, runs the Giant Tortoise Restoration Initiative. It wasn’t easy. Without any Santa Fe tortoises left (nobody alive now has actually seen them – their existence is known mainly from whalers’ logbooks and museum-preserved bone fragments), conservationists turned to a close genetic relative: tortoises from Española Island.

Española is itself a tortoise success story. By the 1960s, the island was so sparsely populated that its 12 females and two males never even crossed paths to mate. Brought to a breeding center on another island, they were joined by a male from the San Diego Zoo, who some naturalists nicknamed “Diego” and who “became the major stud,” Dr. Cayot said. The other two males stepped up too.

The tortoise eggs were incubated, at temperatures adjusted to hatch two females for every male (slightly warmer eggs produce females). At about age 4, able to withstand predators, babies were placed on Española, which now has about 1,000 tortoises, Dr. Cayot said. Santa Fe was next.

Before dawn on June 27, 201 Española tortoises between 4 and 10 years old were ferried there and carried, up to 12 in a backpack, on a long rocky trail to Santa Fe’s interior. The 30 oldest, including two pictured above, have radio transmitters glued to their carapaces.

Periodically, conservationists will find those tortoises to study their movement and effects on vegetation, Dr. Cayot said, noting that about half of repatriated tortoises die because of scarcity of food and water. Those who find what they need are likely to live a century or more.—PAM BELLUCK

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“Our traditional foods are killing our people. But without our traditional foods, we die as a culture.”

—

Vi Waghiyi, who lives on St. Lawrence Island in a remote part of Alaska, home to one of the biggest and most polluted U.S. military sites.

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This aerial footage of hydrothermal vents was recorded by scientists using a drone. Credit
Wildblue Expeditions

That was pretty glorious right? Go back and watch it again. This time look carefully for long, white plumes drifting down the island’s coast. This isn’t sand kicked up by the waves, it’s actually swaths of bacteria thriving off shallow water hydrothermal vents that continuously spew sulfur and carbon dioxide. Scientists think the vents and the life around them may offer some clues to how and where life on Earth started.

The vents are located off Kueishantao Island, near Taiwan’s north east coast. Underwater, the vents look like bubbling chimneys. They heat the water to 212 degrees Fahrenheit and drive the water’s pH way down, to between 1 and 3. (Normal pH of the ocean is around 8.)

“This is the most extreme environment known to humans and oceans in terms of pH, that we know,” said Mario Lebrato, a Spanish oceanographer studying the vents along with a team of scientists funded by the German Ministry of Research, Christian-Albrechts-Universität zu Kiel, and the National Taiwan Ocean University.

Normally these conditions would make it difficult for sealife, but what is so unusual, Dr. Lebrato said, is that the area around the vents is full of crabs and corals.

Dr. Lebrato said the scientists want to know what biological traits allow the organisms to survive. “Life on Earth,” he said, “may have started in similar volcanic sites.”—EMILY HAGER

“Many men think that women are just nagging. But it’s because of their physiology.”

—

Joost van Hoof, a building physicist at Fontys University of Applied Sciences in the Netherlands, commenting on a study of office buildings and the gender-biased formula used to set their temperatures.

Q. On the weather and astronomy page, I saw a “first-quarter moon” depicted as a moon with a vertical slice off the left side. I had always thought of this as a half moon. If it is a quarter moon, is there such a thing as a half moon?

A. The half-illuminated disk of the moon that we see and often refer to informally as a half moon is a quarter of the way along its journey in time from new moon (dark) to crescent moon to full moon (fully illuminated) and back again. It is also a quarter of the way along the moon’s journey in space as it orbits Earth. For that reason, modern astronomers refer to this phase as the first-quarter moon. They also refer to a later “half moon” phase, seen with the vertical slice off the right side, as the third-quarter moon. (The sides are reversed when viewed from the Southern Hemisphere.)

“Half moon” was a familiar term to poets like Shakespeare (1564-1619) and to the Dutchmen who called Henry Hudson’s ship the Halve Maen when it sailed into New York Harbor in 1609. But to confuse matters further, such older sources were often referring to the crescent moon, either waxing or waning.

In reality, of course, exactly half the surface of the moon is illuminated by the sun at all times. What waxes and wanes is not the moon itself but the part of the illuminated side that can be seen by observers on Earth, owing to the changing angles formed by the sun, Earth and the moon.—C. CLAIBORNE RAY

Send your questions to C. Claiborne Ray at questions@nytimes.com. Questions of general interest will be answered, but requests for medical advice cannot be honored and unpublished letters cannot be answered individually.

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To create these images of a soup can and the geneticist Gregor Mendel, scientists programmed a robot to apply tiny droplets of liquid yeast into miniature cells on agar growth plates with sound waves.Credit
Courtesy of NYU Langone Medical Center/Nick Phillips (soup) and Michael Shen (Mendel)

This is no Seurat. It’s not an Andy Warhol. And it’s not your grandmother's cross-stitch, either. Scientists at NYU Langone Medical Center have genetically altered basic yeast and created these images in living color. This is a live yeast portrait of Gregor Mendel, far right, the ultimate nod to the father of modern genetics.

For centuries, humans have played around with yeast. In ancient days, we domesticated it to make beer and bread. This artwork is just a way to visualize the next frontier of yeast manipulation.

A few years ago, the geneticist Dr. Jef Boeke and his laboratory at NYU got together with researchers worldwide to synthetically recreate the 16-chromosome genome of brewer’s yeast. The goal of the effort, called Synthetic Yeast 2.0, is to better understand “the complicated web of genetic interactions that underlie all biological processes,” Dr. Boeke said.

Last year, the research group made its first breakthrough when they created a designer chromosome called “SynIII.” The yeast still worked with this synthetic chromosome, even after 50,000 changes to the original chromosome they manipulated.

Although Dr. Boeke’s “biopointillism,” revealed at a New York Genome Center meeting earlier this month, isn’t part of Synthetic Yeast 2.0, the artwork shows that dabbling with yeast genomes can produce phenotypic, if not behavioral changes.

Naturally, basic baker’s yeast is off-white, but by adding just one gene that produces red fluorescent protein, Dr. Boeke’s lab made it red. To get orange and yellow, they altered genes to pump out beta carotene, the pigment found in carrots. Purple was hard, and green still isn’t perfect. To create the images you see here, a robot picked up tiny droplets of color-producing yeast strains and used sound waves to blast them upward into preprogrammed cells on an agar growth plate. The scientists then incubated the plate, and the colors got stronger as the yeast grew.

The lab can make 10 colors in all, and Dr. Boeke challenges every new member of his lab to add a color to the palette. Dr. Boeke said he was interested in developing yeast strains that could communicate and signal color changes, say from red to pink, when in proximity to one another.

Just for the record, this doesn’t mean you’re going to see purple beer or fuschia bread. Dr. Boeke hasn’t tried it, but he said there was not enough yeast used in the products for the color to show up.—JOANNA KLEIN

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A humpback whale spotted in Alaska on July 12, top. A photograph of what is believed to be the same whale, known as "Old Timer," spotted in August 1978, bottom.Credit
Jim Nahmens/Nature's Spirit Photography; Charles Jurasz

On July 12, researchers aboard a ship called the Northern Song spotted a humpback whale lunge feeding and enjoying some krill in Frederick Sound, Alaska.

It was no ordinary sighting, and the scientists were ecstatic: They say the observation is only the most recent in the longest string of sightings of any humpback in the world.

The whale, whom the researchers named Old Timer, was first seen in Lynn Canal in southeast Alaska 44 years ago by Charles Jurasz, a pioneer in whale research. Old Timer was already fully grown. He is believed to be at least 50 years old now.

“It’s really a celebration of whales since humans largely have stopped hunting them,” said Adam Pack, a biologist at the University of Hawaii and one of the researchers who identified Old Timer.

The whale was immediately recognizable, he said: “Some of these whales have such distinct patterns. It lifted its tail flukes, and we saw the underside.”

In 1990, Old Timer was spotted off the coast of Hawaii escorting a mother-calf pair. He was observed again in 2006, defending his position next to a lone female from other competing males. That sighting confirmed he was male, Dr. Pack said.

Long-term records of sightings help researchers learn more about whales’ fidelity to particular habitats, migratory patterns, female reproductive rates and the behavioral roles that the whales adopt.—SINDYA N. BHANOO

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“By heavens, if this isn’t a sign of climate change, then what is climate change going to bring?”

When the sun sets over New York City, the colorful lights atop the Empire State Building are usually one of the most striking displays across Manhattan’s dark skies. But on Saturday night, that light show was upstaged by another kind of display: projections of images of endangered species lower down on the iconic midtown office tower.

This video captured excerpts of the work of Louie Psihoyos and Travis Threlkel, the artists who cast digital images of a variety of threatened animal species across the Empire State Building’s south face on Saturday. Mr. Psihoyos explained that they had set out to do “the most dramatic thing we could do to get the world to know about what we’re losing.”

To make their statement, the artists used 40 projectors on the roof of another building a few blocks south. And whether the project succeeded in expanding awareness of threats to the planet's biodiversity, it made an impression on some of the people who gazed upon it firsthand.

“Witnessed some spectacular Big [Apple] magic last night,” wrote Becca Zoler, an Instagram user, with a photo she posted of the display.

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A lifeguard jumping into a pool to save a drowning child. Reveal the drowning childCredit
YouTube/Parklands Foundation of Charleston County

Can you spot the drowning child in the image here? An average of 10 people a day die from unintentional drowning according to the Centers for Disease Control and Prevention, but often it’s a quiet struggle that hardly resembles the dramatic affair we see on television.

Software engineer Francisco Saldaña created the simple educational game spotthedrowningchild.com to help people recognize the deadly situation. A person who is drowning is physiologically incapable of calling out or waving for help – meaning often there is little noise or splash.

In his marine safety guide Mario Vittone, a Coast Guard veteran, describes some things to look for instead:

The individual’s mouth bobs above and below the surface while the body remains upright without evidence of kicking.

The individual’s arms spread to the side and push down against the water to try and push their mouths out of the water.

The videos that Mr. Saldaña used show lifeguards successfully rescuing children from drowning and come from the YouTube channel of the Genesis Project in Charleston County, which aims to reduce the number of drownings in rural areas by providing access to swimming and water safety classes.—ALBERT SUN

That salmon-colored expanse is a colony of the pathogenic bacterium Pseudomonas aeruginosa, a source of infections that is familiar in hospitals. The grid beneath it is an electrochemical camera chip, a new tool that researchers at Columbia University are using to better understand the behavior of communities of bacteria.

The camera chip’s electrochemical imaging process is something like “taking a movie” over time, said Dr. Ken Shepard, a professor of electrical engineering and biomedical engineering and one of the researchers on the project. By recording the chemical activities of the bacteria, the researchers are able to learn more about the mechanisms that individual cells use to organize themselves into a community. Marshaling one billion individual P. aeruginosa cells into the colony formation pictured here, for instance, required a considerable amount of coordination on the part of the cells.

When bacteria coalesce to form multicellular structures, they secrete what are known as signaling molecules. This new electrochemical camera chip can detect the distribution of these molecules and interpret that information to find patterns that suggest how individual bacteria communicate with one another when they organize into these impressive multicellular communities.

Dr. Shepard and his colleagues direct the colonies by manipulating conditions on the chip — for example, the presence or absence of oxygen. Then, the camera chip observes how the bacteria respond under those different conditions. By measuring the concentration and distribution of phenazines, a type of signaling molecule emitted by P. aeruginosa, the camera chip is “able to extract temporal and spatial patterns” from the bacteria’s reconfiguration, Dr. Shepard explained.

Identifying how these multicellular structures form is critical to learning how to disrupt that formation. And because some cell configurations are known to contribute to antibiotic resistance, there is a very real benefit to furthering our understanding of how to interfere with the behavior of bacteria.

Not quite as easy as snapping a photo, but it can be done.—LOUIS LUCERO II

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“If work were going well and you had a great relationship, you wouldn’t get the chance to drink with people.”

—

An excerpt from a chat with Xiaoice, a popular Microsoft chatbot that mines the Chinese Internet to make conversation with people.

People have been killing a lot of lions for a long time. How many? In a major report in 2009, the International Union for the Conservation of Nature estimated that hunting tourists killed 105,000 animals per year. That included 3,800 buffalo, 800 leopards, 640 elephants and 600 lions — more than 2 percent of the lion population.

But for them the world is a reverse "Cheers." Nobody knows their names. The death of Cecil — dark-maned, living in a park, studied by scientists and known to tourists — was greeted as tragic. It was illegal to kill him, which no doubt accounts for some of the uproar. And he certainly looked appealing in photos.

But you can't underestimate the importance of a name. When you name another creature, you assign it a certain status. You might name a pet pig, but probably not one destined for bacon.

There are about 20,000 lions left in Africa according to Panthera, a conservation group. Imagine if they all had names. Pessimists may object that it's hard to name 20,000 animals, but we have computers. There's already a website that advertises 20,000+ names.

If you don't think this will work, here's a test. Say the following two sentences out loud and see which one makes your eyes mist.

600 lions are shot by hunters each year.

They killed Betty!

Tissues, anyone?—JAMES GORMAN

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A plane flew by a blue moon in August 2013. Following Friday's blue moon, the next will be in 2018.Credit
Julio Cortez/Associated Press

Once every two or three years, a blue moon will grace our sky. This Friday, look up and you’ll see it.

It won’t be blue, nor really as rare as the saying might imply. You might say its specialness is simply that it is extra. The popular definition is that it is the second full moon in a calendar month. Farmer’s Almanac calls it the fourth full moon in an astronomical season, which usually has just three.

A truly blue-colored moon can result following a dust storm or volcanic eruption when super tiny dust particles refract blue light. That’s rare.

Full moon fun fact, blue or not: researchers have found that some doodlebugs dig deeper holes to catch prey during this time in the lunar cycle.—JOANNA KLEIN

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Graphene can be folded and cut into a microscopic kirigami spring.Credit
Cornell University/McEuen Group

Now researchers have discovered another one of graphene's feats: It's as flexible as paper. Not only can graphene be crumpled and then perfectly flattened, but it can also be folded like origami, according to a report published Wednesday in Nature.

Using a style of origami that involves cuts and folds called kirigami, the researchers fashioned a sheet of graphene into a tiny spring. According to Nature, researchers may one day use kirigami to craft graphene sheets into microscopic weighing scales or nets small enough to wrap around living cells.—NICHOLAS ST. FLEUR

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“What’s amazing to me is that it is out there for sale on the Internet.”

—

Don Catlin, an expert on testing for banned substances, on two cyclists' positive drug tests suggesting use of an experimental drug not yet been approved for human consumption.

For almost a century, the Saltwater Cowboys of the Chincoteague Volunteer Fire Department have been wrangling up wild ponies and sending them on a 4-minute swim across the Chincoteague Channel, just off the coast of Virginia. The last Wednesday and Thursday of July are the days that the ponies paddle 75 yards to the other side of the water on Wednesday before parading through town to be auctioned off on Thursday.

Some locals call the ponies wild, but they are actually feral, meaning at one point they escaped domestication. The most popular origin story is that the Chincoteague ponies survived a 17th Century Spanish shipwreck. With little evidence to support that popular tale, however, a more plausible one is that settlers kept ponies on the island to avoid a 1669 horse tax.

Over their 400 year history, these island mutts have demonstrated a keen ability to stick around. They’re short and stocky; svelte in the summer, puffy in the winter. They survive on marsh grasses and poison ivy – whatever they can get their snouts on.

With no apex predators, the two herds on the island would be a problem if not managed. Grazing ponies would disrupt fiddler crab activity and take food and nesting habitat from other animals like deer and marsh birds, according to Kelly Taylor, science communicator at Assateague Island National Seashore.

Along with being a good way to raise funds for the Chincoteague Volunteer Fire Department, the auction of their private herd on the Virginia side of the island reduces the population and protects the environment. On the Maryland side however, the National Park Service can’t sell public wildlife, so they put their herd on birth control. Only the Virginia ponies take part in the swim.—JOANNA KLEIN

Correction: July 30, 2015: An earlier version of this post misstated the day the ponies swim each year. While it occurred on the last Wednesday of July this year, if July 31 is a Wednesday, the swim occurs the week before.

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Machias Seal Island is home to Maine’s largest colony of puffins.Credit
John Schwartz/The New York Times

When we planned our family vacation this year, we had one thing in mind: puffins. Our daughter, Elizabeth, was coming to visit, and she’s always been just plain puffin crazy. She got a puffin tattooed on her hip when she was in college, and had found out about a boat trip that takes visitors to Machias Seal Island, home to the largest colony of puffins along the Maine coast. Between May and August the seabirds nest, laying a single egg per mother, and near the end of the season the little pufflings come out of their burrows to begin their own migratory lives.

Upon arriving on the 15-acre island, we headed to a small blind. The puffins come within a few feet of the small gray structures — and cluster by the dozens up on top. We were warned not stick our hands out the window or to do anything else that would remind the puffins of our presence. Too much exposure to humans, our guides said, agitates them.

The adult puffins seemed oblivious to us as they toddled around, knocking into each other on their crowded rocks and darting down into the burrows with beaks laden with fish for their hungry young. The little pufflings emerge from their cozy dwellings and generally begin their seafaring life in August. (You can see what they are up to down there, on another island, via the Audubon Society burrow cam.)

On the way back from the island, my daughter showed her tattoo to our fellow passengers and crew. They found the depicted bird exquisitely detailed, and stood up well to the real thing. They expressed this, largely, by saying, "Whoa!"—JOHN SCHWARTZ

A number of operators offer a glimpse of puffins from a boat. For those who want to get as close as John Schwartz did, Bold Coast Tours offers its customers a chance to step onto Machias Seal Island. You can find out more about efforts to restore puffins to Maine's coastal islands here.

About 15 to 20 million years ago this lizard, an anole, was trapped in tree resin that later turned to amber on the island of Hispaniola. Anoles still live in abundance on the island and throughout the Caribbean, and Jonathan Losos, an evolutionary biologist at Harvard, was interested in understanding how their communities have changed over the years.

To do this, he gathered almost every known anole fossil from this time and place, with the help of colleagues and collectors around the world who prize examples of life caught in resin as both gems and fossils.

After analyzing the 20 best preserved examples, he found that not only are the lizards much the same now as they were then — no surprise — but so is the way the anoles divide their rain forest home. The nature of their ecological community has remained unchanged.

Anoles occupy very specific bits of space on trees in the rain forest, and their body shape tells their niche. The anole pictured here has the long, narrow head and short limbs of trunk-to crown anoles. They live now on the trunks of trees above about six feet up to the crown. Other anoles live in the crown; and yet others live on the trunk, but closer to the ground.

Scientists are skeptical that these kind of ecological divisions last over great stretches of time. But this is one case in which they did. By 20 million years ago, Dr. Losos said, the anoles had already evolved the body shapes that show how they shared their world. And since the shapes have stayed the same all that time, he concludes, so has the shape of their community. Trunk-to-crown, ground-to-trunk — they have occupied the same niches for all these millions of years

One unsolved mystery about this particular anole is that while its whole body was preserved, its internal organs and skeleton seem to have rotted away and disappeared.—JAMES GORMAN

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Echinopsis flowers often look their their best for just two hours.Credit
Greg Krehel

Rest your head and you could miss an echinopsis flower. Some varieties bloom and wilt in just a few hours. So Greg Krehel — who owns more than 100 different varieties and hybrids of echinopsis, a kind of cactus — decided to do something to capture these short, vibrant lives.

Mr. Krehel, a software start-up consultant, started with still images. But photos didn’t capture the thrill of a flower’s life. Time-lapses, he decided, would better highlight the speed at which the flowers change.

Now he condenses the time it takes for the petals to open – often under 10 hours, and rarely more than a day – into just a few vibrant seconds of video, which he posts on Instagram

Mr. Krehel, a longtime cactuses lover, was introduced to echinopsis about five years ago when a cactus he picked up at a garden shop started blooming — and blooming. “It was like, ‘Well what the heck is this?’” he recalled.

Looking back, he said, his first plant “was a snoozer compared to some of the other ones that are out there.”

At his home in Jacksonville, Fla., Mr. Krehel now has a collection of about 150 plants acquired from sellers across the United States. Echinopsis are fairly easy to grow, he said. In Jacksonville, they live in pots.

Mr. Krehel said he has learned how to tell when one of his plants is ready to bloom, watching as the growth rate of the flowers speeds up. When the time comes, he brings his subject into a makeshift studio — a bathroom equipped with a photo tent — and sets up to shoot 80 frames an hour over the course of a night. The resulting videos show the flower as it explodes into a vibrant bloom — and sometimes go on to depict the wilting process.

At the end of the night, he returns the plant to its home outside and waits for another bloom to appear. The length of the blooming season varies, he said, but in Florida it starts in April and ends in October.

For echinopsis, beauty comes with age. While there are differences among hybrids, in general the older plants bloom more often and show off more flowers – sometimes as many as 30 in a single season.

—KERRI MACDONALD

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“These owners think, ‘My cat only kills two mice a day.’ But they don’t think about the high density of well-fed cats throughout their neighborhood.”

—

Sara J. Ash, a professor of ecology and conservation biology at the University of the Cumberlands, on a study of cat owners and how they perceive their pets' effects on wildlife.

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Only the second ever found, this tiny pocket shark was discovered by NOAA scientists in the Gulf of Mexico in 2010 and identified in 2013 by researchers at Tulane University.Credit
Michael H. Doosey/Tulane University

None of this is helping sharks’ deep-seated image problem. (Even clouds shaped like sharks are considered to be terrifying.) As an antidote to panicky associations with the toothy creatures, we offer the six-inch pocket shark.

“It’s a funny little shark,” said John Maisey, a shark curator at the American Museum of Natural History. “It has a round bulbous head, it tapers down to a funny little forked tail, and you can fit it in the palm of you hand.”

Using a CT scanner, Dr. Maisey and researchers from the museum imaged this beady-eyed oddity. Since only two pocket shark specimens have ever been collected, researchers resist investigating its insides with invasive tools like scalpels. Their next steps are to focus more powerful scanners on specific structures of the shark’s anatomy, such as its skull, jaws and soft tissue areas.

One reason the pocket shark is a rare find is that it lives in moderately deep water, too far down for divers but not deep enough to be spotted with tools that observe the ocean floor. “It affirms there are things we can still find that are unusual and odd,” said Dr. Maisey.

But what is most curious about the pocket shark, according to Dr. Maisey, are the narrow slits or “pockets” on its sides just above its fins. No other shark has these structures. Scientists are not sure exactly what the pockets are meant for, and some guess they might release glow-in-the-dark fluids for catching prey or a mate. Because so few of the sharks have been found, it may take scientists a while to solve the mystery.

But according to Dr. Maisey, one thing’s for certain: “It is not holding spare change in its pocket, we didn’t find any.”—NICHOLAS ST. FLEUR

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‘‘They will never make a movie about him. He doesn’t have a troubled life. He has a family, and they seem happy, and he’s usually smiling.’’

—

A student of Terry Tao, a mathematician who is regarded by many as the finest of his generation.

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Unlike other fish, which eventually get full, these fat fish just keep going. Credit
Harvard Medical School

They're blind and fat and they are insatiable. They will eat anything – guano, black worms, dead and decaying fish – and they will keep eating until all the food is gone. Unlike other fish, which eventually get full, these fat fish just keep going. They are Mexican cavefish, which adapted to living in the dark by losing their eyes – no need to see – and adapted to living in a place where food is only available twice a year when the river floods by getting as fat as possible. They also have a slow metabolism so they keep the fat on.

They are weird fish, for sure, but what makes them especially interesting is what they might reveal about human obesity. They have a mutation in melanocortin 4, a receptor gene also known as MC4R that also makes people grow fat, reports Clifford Tabin of Harvard and his colleagues in Proceedings of the National Academy of Sciences. About 6 percent of very obese children have an MC4R mutation.

About 1 in 1,000 Caucasians have an MC4R mutation, making the syndrome as prevalent as cystic fibrosis. It is the most common single gene cause of obesity, and one of the most common genetic disorders in humans.

Like the fish, many obese people with an MC4R mutation have huge appetites starting in the first year of life. They cannot help getting fat – their craving for food and their lack of satiety overwhelm any attempts to diet. But unlike people with the MC4R mutation, the fish are healthy. They have enormous fatty livers, but no liver disease. When they eat, their sugar levels shoot up and stay so high you would swear they are diabetic. Yet they are not. (Fish, like humans, have insulin receptors and can become diabetic.)

Those fish, Dr. Tabin says, must have other mutations that allow them to avoid the consequences of obesity. If researchers could identify these genes, it might be possible to mimic their effects with drugs. So, he says, although it may not be possible to eliminate human obesity, at least in the foreseeable future, the fish could lead to ways to help overweight people stay healthier, even if they cannot lose weight.—GINA KOLATA

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“We come together as a group to tell the others that nothing is there that they can do that we cannot do.”

—

Erison Turay, a survivor of Ebola, on why he started a soccer club for other Ebola survivors in Sierra Leone.

Update: We've heard from some readers who thought that the first updated "Blue Marble" photo was of the same region of the planet as the 1972 image. That's not the case. The Apollo 17 crew took a photo, left, which extends from the Mediterranean Sea area to the Antarctica south polar ice cap. There is heavy cloud cover in the Southern Hemisphere, while the coastline of Africa is visible. The Asian mainland is on the horizon toward the northeast. The image taken on July 6, 2015, center, was of the other side of the planet and North and Central America are most clear. On July 29, a third "Blue Marble" image, right, was released that shows Africa front and center. Central Europe is toward the top of the image with the Sahara Desert to the south.

On Tuesday we shared NASA's new photo of a fully illuminated Earth. This is an update to the “Blue Marble” photo taken by Apollo 17 astronauts in 1972, more than four decades ago.

Here, you can compare the two.

“How perfect North America looks. I am still amazed by how the oceans dwarf the continents,” Jim Corradino of Norwalk, Conn., wrote us.

“There’s something remarkable about a single snapshot of the Earth — an intact view of our planet in its entirety, hanging in space,” the astronaut Scott Kelly observed in an essay on Medium. He explained what makes these images so special. Along with the challenge of getting far enough away to get the entire Earth into a single frame, there is the matter of lighting.

“In order to view the Earth as a fully illuminated globe, a person (or camera) must be situated in front of it, with the sun directly at his or her back,” he wrote. “Not surprisingly, it can be difficult to arrange this specific lighting scheme for a camera-set up that’s orbiting in space at speeds approaching thousands of miles per hour.”

Consequently many of the images of Earth we see are actually composites. This is just the first in a series of images of Earth that will be sent back from a million miles away. We will soon see the other side, fully illuminated as well. (Update: you can find the other side here.)—HEATHER MURPHY

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“We can’t say it’s impossible, but if there is a risk it would be very, very low, or we would have seen an increase in brain cancers.”

—

Jerrold T. Bushberg, a medical physicist and a professor of radiology and radiation oncology at the University of California, Davis on the risks of radiation emitted by cellphones. A Berkeley, Calif., measure requires cellphone stores to warn customers of health hazards.

This photo shows an stockpile of elephant and rhino tusks that have been seized by the Kenyan government. Scientists gathered data about the collection at Kenya Wildlife Services headquarters in Nairobi on Tuesday.

More than two decades after a ban on ivory trade, Asian demand still fuels illegal poaching of elephants and rhinos in Kenya.

The Kenyan government has said that it wants the world to see these animals for their beauty rather than economic gain. In March, President Uhuru Kenyatta of Kenya burned 15 tons of elephant ivory worth $30 million and plans to destroy the rest of the stockpile by the end of the year, according to BBC News.—JOANNA KLEIN

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“We have a responsibility to not stop searching. It should always be happening in the background. This is the biggest question. We should be listening.”

Forty six years ago, Neil Armstrong and Buzz Aldrin landed on the moon. Readers of The Times were greeted the next morning with a famous headline, "MEN WALK ON MOON," and a paper that included transcripts, a front page poem, reactions from all over the world (Pablo Picasso and the Dalai Lama are worth reading) and a full page essay by George E. Mueller, a NASA official.

Dr. Mueller attempted to forecast the next decade of American missions to space. Some of what the NASA official proposed - an orbital space station serving as a laboratory and reusable shuttles - eventually came to pass. But much of what he hoped for did not occur:

NASA planned nine more landings on Earth's satellite. NASA only completed six landings.

The essay described the advantages of a nuclear-powered base on the moon that would create a breathable atmosphere and house explorers. A couple of months ago, humanity did succeed in sending an espresso maker to the International Space Station. But we've yet to build an extra-terrestrial base.

Dr. Mueller proposed spacecraft with nuclear-fueled engines that would remain in orbit and transfer personnel from a station orbiting Earth to one that would orbit the moon, and then to the moon itself. As the recent Pluto mission has demonstrated, securing enough nuclear fuel for a piano-size spacecraft is still a challenge.

The essay concluded: "By the end of this decade the moon could be, and I believe will be, regularly visited." Though this dream continues to be pursued in some ways, humans have not visited the moon since 1972.—MICHAEL ROSTON

The Cuban hutia, a button-nosed, furry rodent the size of a dachshund, is said to be shy by nature.

But the hutias we met on a small mangrove-covered cay during an expedition to Jardines de la Reina, an archipelago off Cuba’s south coast, seemed more the social butterfly type — probably because they live in a protected marine preserve.

They greeted us when our skiff reached the beach, and were happy to stick around for a drink. While some might see them as oversized rats, these hutias were pretty cute.

Also known as Desmarest’s hutia, the whiskered mammal is found only on Cuban soil and is the largest of the hutia species. It lives on plants, fruit and the occasional small reptile, but has a special fondness for mangrove roots.

Digestion is no problem: The hutia’s three-compartment stomach is known for its complexity. It is illegal to hunt hutias in Cuba without a special permit, but occasionally they end up in stew. Legend has it that the rodent provided the first meat Christopher Columbus tasted in the New World.—ERICA GOODE

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A new close-up image of an area on Charon, Pluto's largest moon, reveals a feature that has geologists stumped. Jeff Moore who leads who leads New Horizons’ Geology, Geophysics and Imaging team called it a "large mountain sitting in a moat.” Charon is the name of the ferryman of Hades in Greek mythology, and the wife of the scientist who discovered the moon is nicknamed "Char."Credit
NASA

Some confusion has arisen about how to pronounce the name of Pluto's main companion, Charon. We talked about it with James Christy, who discovered Charon by seeing Pluto looking suspiciously elongated on a photographic plate back in 1978.

Dr. Christy, an astronomer at the United States Naval Observatory at the time, decided to name the new object after his wife Charlene, whose nickname was Char. And so, he and she maintain, the moon's name should be pronounced Shar-on (with the sh like Cher, not chair and the ar like bar), not Karon or Chair-on as some commentators have said.

You can hear him say Charon here and explain the moon's origin story here. (Pardon the background noise, this was recorded amid the celebrations at NASA's lab in Maryland.)

An earlier version of this post misspelled the surname of the wife of the discoverer of Charon. She is Charlene Christy, not Christie. Additionally, a caption with an earlier versio of a photograph with this post misstated the first name of Ms. Christy. She is Charlene, not Charon.

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Earth as seen on July 6, from a distance of almost one million miles by a NASA scientific camera on board the Deep Space Climate Observatory spacecraft.Credit
NASA

At first glance, it's a picture of Earth. Not much different from all those pictures of Earth you've seen over the years.

That is, until you realize that most of the pictures of Earth you've seen over the years have been the same photograph — the “Blue Marble” taken by Apollo 17 astronauts in 1972, more than four decades ago.

There are not many photographs showing a fully illuminated Earth, because the camera has to be between the Earth and sun, while far enough away to capture the whole planet. Weather satellites in geosynchronous orbit can get a similar view, but not quite the entire hemisphere. Also, they are over a single location and the planet is partly in shadow most of the time.

Now, the Deep Space Climate Observatory, or Dscovr for short, will be taking such photographs on a regular basis, always over the dayside of Earth. The first was released on Monday.

The spacecraft started out as "Triana," a pet project of former Vice President Al Gore in 1998 who thought it would be inspirational and educational for a satellite to continually send back a view of a changing Earth from almost a million miles away. Opponents derided it as "GoreSat," and the finished spacecraft was put in storage.

It was resurrected by the National Oceanic and Atmospheric Administration to look the other way, at the sun, to serve as a sentinel of oncoming solar storms. But the Earth-facing camera is still there and now is finally taking pictures.—KENNETH CHANG

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“For me, this is among the purposes of my life — to take us from states of ignorance to states of understanding with bold exploration that you can’t do every day.”

—

Claudia Alexander, who played a pioneering role in NASA’s Galileo mission to Jupiter and the international Rosetta space-exploration project. She died at age 56 on July 11.

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What they say from Pluto took their breath away.Credit
Jason Drakeford, Robin Lindsay and Andrew Blackwell

Scientists had a lot riding on the New Horizons mission to Pluto. First, there was the audacious expectation that a spacecraft launched nearly 10 years ago would go exactly where it was expected to go, billions of miles away. Second, there was the belief that what we'd learn from the dwarf planet would make all the waiting worthwhile.

For the scientists working on the mission, these expectations were more than exceeded.

“Jaw-dropping” and “amazing” were some of the adjectives used by Hal Weaver, a project scientist.

“We're like inmates in an asylum; it's bedlam,” said William McKinnon, a New Horizons co-investigator.

Later today, we'll find out whether the latest images of Pluto and its moons can take our breath away again.

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Members of the New Horizons spacecraft mission viewed new images of Pluto on Wednesday. Additional images and findings will be released Friday afternoon.Credit
Bill Ingalls/NASA, via Associated Press

At a 1 p.m. news conference on Friday, to be broadcast on NASA TV, scientists on NASA's New Horizons mission to Pluto will discuss some of their latest findings after mulling what they have seen in the first two days' worth of data sent back from the spacecraft.

That will certainly include more stunning photographs like the close-up snippet of Pluto's surface that came out on Wednesday. That is likely what Jeffrey Moore, the lead of the mission's geology and geophysics team, will talk about.

The news will probably go beyond the photographs to some of the more esoteric data. Another scientist scheduled to speak is Fran Bagenal of the University of Colorado at Boulder. Her expertise is how the solar wind — the stream of charged particles spewed by the sun — behaves when it intercepts a planet (or dwarf planet) like Pluto.

The news conference will also feature Randy Gladstone, the head of the atmosphere team, perhaps providing some information about Pluto's thin air, which like Earth's is mostly nitrogen. The dynamics of the atmosphere probably have a lot to with the wide variations in brightness on Pluto's surface.—KENNETH CHANG

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“The more roughness they have, the more scary people ranked the screams.”

—

David Poeppel, a neuroscientist at New York University and the Max Planck Institute in Frankfurt, on a study of human screams.

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The front page of The New York Times as it appeared on July 16, 2015, and July 16, 1965

On Thursday, NASA's New Horizons spacecraft beamed close-up photos of Pluto back to Earth for the first time. Exactly fifty years earlier, NASA pulled off a similar feat when the Mariner 4 spacecraft sent home the first images of Mars. The photos were featured at the top of the front page of The New York Times on both days.

Quite a bit has changed in the succeeding decades, but the differences in the speed at which the photos made it home are particularly remarkable. An article in The Times in 1965 noted that it took eight and a half hours to send a single image from Mars to Earth, at a speed of 8.3 bits a second. Patience was still required to receive a single image from Pluto, but across a distance of billions more miles from Earth, New Horizons was sending us images at 1,000 bits a second.

However long it took to see those images for the first time, on both days, readers of this paper could take delight in finding an otherworldly scene delivered directly to their doorsteps.—MICHAEL ROSTON

"The director of astrovisualization looks more like a rock star," was one comment on our recent documentary on Pluto. "That dude looks so hip," was another.

Needless to say, Carter Emmart, the Director of Astrovisualization of American Museum of Natural History was a hit with our viewers. He was there nine and half years ago when New Horizons headed off to Pluto. And he was there Wednesday, as NASA showed off the first close-up image of ice mountains.

In 1991, the United States issued a set of 10 stamps: one for each planet plus for one for the Earth's moon. The stamp for Pluto showed a blurry globe with a simple statement: Not Yet Explored. Among the memorabilia on the New Horizons spacecraft is one of those 1991 Pluto stamps, by far the farthest that 29 cents of postage has ever traveled.

On Tuesday, the New Horizons team held up a large reproduction of the Pluto stamp with "Not" and "Yet" crossed out.—KENNETH CHANG

It took ten years and 4.7 billion miles, but on Wednesday NASA's New Horizons spacecraft zipped past Pluto on its galactic road trip.

For folks at Johns Hopkins Applied Physics Laboratory in Laurel, Md, the occasion called for one very special hat. Here Matthew McNutt (left) and Elysse Camacho (right) celebrated the flyby Tuesday. McNutt's physicist father, Ralph McNutt, was working on the mission.—JOANNA KLEIN

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The images released Wednesday will have 10 times the resolution of this image.Credit
NASA, via Associated Press

The first high-resolution close-ups of Pluto’s surface traveled three billion miles to arrive on Earth this morning. On Wednesday afternoon, NASA will release them to the public. The images will have 10 times the resolution of the photo of the icy planet released on Tuesday.

What to expect

At least one close-up of the region that people are calling its heart.

NASA might also release a 3D image of some part of the planet's surface along the lines of this landscape from Mars. (Get your 3D glasses ready!)

A high-resolution image of Charon, Pluto’s largest moon.

The crispest photos ever made of Nix and Hydra, Pluto’s two smaller moons, which were discovered in 2005.

When

New Horizons team members will discuss the images in a news conference on NASA TV from 3 p.m. to 4 p.m. Eastern time.

We are also prepared for them to release the pictures earlier in the day. On Tuesday, the space agency posted the new photo of Pluto — the last and most detailed one taken before the flyby — on their Instagram account, ahead of the formal release of a higher resolution version.

Beyond Photos

Hal Weaver, a New Horizons project scientist, said Tuesday that the first batch of Pluto flyby data will also include information about what's in Pluto's thin atmosphere and the temperatures on the night side.

The instrument pictured hurtled past Pluto at 31,000 miles per hour aboard NASA’s New Horizons spacecraft Tuesday morning. It could provide the lesson plan for a master class in energy efficiency all by itself.

What does SWAP — as the instrument is called — stand for, and how much power does it use?

Solar Wind Around Pluto, one of seven scientific instruments built into New Horizons, was projected to run on 2.3 watts, but in practice requires only about 1.2 watts — significantly less power than a dim night light. That energy efficiency is a particular boon on a spacecraft as light as New Horizons, where every ounce of weight must be carefully accounted for: Indeed, all seven instruments run on a single generator and draw less than 28 collective watts.

“Space instruments in general are incredibly stingy in power,” said Dave McComas, assistant vice president for space science and engineering at the Southwest Research Institute in San Antonio, Tex., and the lead investigator for SWAP.

SWAP’s purpose is to observe interactions between solar wind — the stream of charged particles thrown off by the sun in all directions at every second of the day — and the gases that escape Pluto’s atmosphere because of a relatively weak gravitational pull. Studying those interactions will afford researchers a vital glimpse into the composition of the dwarf planet’s atmosphere.

The instrument was not originally expected to collect solar-wind data throughout the entire three-billion-mile journey. “We got permission from NASA to operate during hibernation,” said Heather Elliott, the SWAP instrument scientist.

Now, nine and a half years after launching from Florida, SWAP has data to show for some 90 percent of the voyage — all of which provides a terrific baseline against which to compare the data acquired in Pluto’s vicinity. —LOUIS LUCERO II

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This video contains big cosmic thoughts, flyby excitement and a New York Times reporter in a ridiculous hat. Credit
Jason Drakeford and Sofia Perpetua

Scientists, engineers, journalists and an assortment of V.I.P.s are currently playing the cosmic waiting game at the Johns Hopkins Applied Physics Laboratory in Laurel, Md.

At 8:53 p.m Eastern Time Tuesday, New Horizons is supposed to call and essentially say, "Hi, I'm still alive." The transmission, which is to last until 9:09, is to provide a quick summary of how the day went. That is to be the first communication from the spacecraft in 22 hours. (It will not include any photographs. A little more patience is required for those.)

Now that NASA's New Horizons spacecraft has completed its Pluto flyover, we're anxious for the next space expedition.

Earlier this week we asked our readers to vote on what they think NASA should explore next. On Tuesday we posed that same question to Neil deGrasse Tyson, director of the Hayden Planetarium and host of National Geographic's "Cosmos."

Dr. Tyson said he has his eyes set on Jupiter’s moons.

“I want to go ice fishing on these icy moons of Jupiter, especially Europa,” he said in an interview at the American Museum of Natural History after the historic flyby Tuesday.

Astronomers have long flirted with the idea that Jupiter's moons could harbor the ingredients necessary for life. Previous findings have suggested that oceans exist beneath the surfaces of Jupiter's moons Europa, Callisto and Ganymede.

“Every place on Earth where there’s liquid water, there’s life," Dr. Tyson said. "So your next round of questions are, ‘Is there life on those objects?’”

In June, NASA moved forward on constructing a plan to investigate Europa. Early proposals favored sending a spacecraft to orbit the moon. But NASA decided against that because radiation from Jupiter engulfs Europa, and an orbiter would probably be fried if stayed too close to the moon for too long, the researchers said.

Instead, they have proposed sending the spacecraft to orbit Jupiter from a safe distance away from the radiation and then perform frequent flybys of Europa. The craft will perform about 45 of these maneuvers during its three-year mission, according to NASA.

Like Dr. Tyson, NASA's astronomers hope the spacecraft will provide tantalizing details about the potential for life to exist elsewhere in our solar system.

The agency plans to launch the mission in the 2020s.—NICHOLAS ST. FLEUR

After nine and a half years and three billion miles, NASA’s New Horizons spacecraft zipped past Pluto and its five moons on Tuesday morning. NASA shared the last photo sent back to Earth before the flyby Tuesday, shown here. New Horizons will send back at least one higher-resolution image on Wednesday, but the rest of the photos will remain stuck on the spacecraft for months.

Why? Because sending them back takes lots and lots of time.

Imagine someone speaking to you softly from the other side of a large room. You might be able to barely hear him but to make out the words if he spoke very, very slowly.

NASA's New Horizons spacecraft is at the edge of the solar system, nearly three billion miles away. Its radio transmitter puts out a tiny 12 watts of power, about the same as an LED bulb in a table lamp.

Even with a huge 70-meter radio dish on Earth listening to the faint transmissions, that means New Horizons has to talk very, very slowly.

As New Horizons starts sending its trove of flyby data back on Wednesday, the pace will be at a glacial 1,000 bits a second. That is roughly the rate at which computer modems talked to each other in the mid-1980s.

Photographs taken by the spacecraft's black-and-white camera measure 1,024 pixels by 1,024 pixels, or more than a million pixels in total. Each pixel consists of 12 bits, to record one out of 4,096 possible gray levels. That's more than 12 million bits of information in each picture.

To send that all back at 1,000 bits a second would take 12,000 seconds, or 3 hours and 20 minutes. Images can be compressed, but even if squeezed to a tenth of the original size, one photograph would still take 20 minutes to download.

New Horizons is taking a lot of pictures and collecting a slew of other measurements, too — so much that it would take three months to send all of it back if New Horizons could get exclusive use of NASA's Deep Space Network, the system of radio telescopes that communicates with distant space probes.

But the network is also needed to talk to NASA's many other space probes, so 16 months will pass before scientists can get their hands on all of the data from this week's flyby.

This week, the New Horizons team will retrieve a few choice images and snippets of what they think will be the science highlights.—KENNETH CHANG

The New Horizons team and the Applied Physics Laboratory have left no stone unturned in the effort to keep Plutophiles entertained and engaged while they await New Horizons' daredevil pass by Pluto Tuesday morning. On Monday morning under a hazy humid sky in the suburban Middle Earth between Baltimore and Washington, D.C., V.I.P.s, journalists and other special guests descended on Johns Hopkins Applied Physics Laboratory. Among them was Barbara Mikulski, the retiring senator from Maryland who has been a bulldog over the years fighting for funding for NASA and space exploration.

The public program started off with a dramatic video complete with woo-woo music, and many jokes about how the speakers weren’t going to joke about Pluto’s demotion.

Midway through the afternoon S. Alan Stern, the mission's principal investigator, took the stage. He has never made any bones about his disagreement with the International Astronomical Union’s decision back in 2006 to demote Pluto to the status of a dwarf planet. He pointed out that with the discovery of the Kuiper Belt, Pluto is not a misfit anymore. It’s only in the middle, size-wise, when Kuiper belt objects are included in the roll call of the solar system.

He chided his fellow astronomers for not wanting to extend the number of planets when Kuiper belt objects started piling up. But as Dr. Stern pointed out, the small things are winning.

“You can see Pluto is perfectly spherical just like any respectable planet. God bless my space agency. Some day they ARE going to get on board with how popular this is,” he said.

He got a standing ovation.—DENNIS OVERBYE

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An image from the music video for Pluto's latest song.Credit
Craig Werth and Christine Lavin

Access to mission control at Johns Hopkins University Applied Physics Laboratory on Tuesday morning is extremely difficult to obtain. As New Horizons flies by Pluto the room will be filled with a select group of scientists and engineers, who contributed to its nine-and-a-half year journey in some way. Two people obtained an invitation from S. Alan Stern, the mission's principal investigator, in recognition of a scientific contribution of another kind: a song.

“He was quite taken with it,” said Craig Werth, the writer and singer of “Oh Pluto,” a starry-eyed folk greeting to the distant planet.

We are your distant neighbors, from the planet that is blue, and we’re coming for a visit, with the hope of knowing you. You may have felt the buzzing, as we’ve studied from afar, we take a special interest in, all that shares this yellow star.

“I don’t want to bring you out if you’re going to sing about Pluto not being a planet,” Dr. Stern, who firmly believes Pluto is a planet, told her. “It’s too much of a team downer at flyby.”

Ms. Lavin reached out to Mr. Werth, another folk singer, who she thought could create something more to Dr. Stern's liking.

Among the people who make cameos in the music video are Dominic Chianese, the actor who played Uncle Junior in “The Sopranos,” intoning “Hello, Pluto!” and Noel Paul Stookey, the Paul of Peter, Paul and Mary.—KENNETH CHANG

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An artist's rendering of Pluto as viewed from the surface of one of its smaller moons.Credit
NASA

Scott J. Kenyon, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., has a prediction about Pluto: NASA's New Horizons spacecraft will discover more moons.

A new paper by Dr. Kenyon and Benjamin C. Bromley of the University of Utah pinpoints places where moons — and even rings, like a miniature version of Saturn's — could be lurking around Pluto.

Within a week or so, Dr. Kenyon will likely know whether he is right or wrong.

Pluto has five known moons, more than Mercury, Venus, Earth and Mars put together. The biggest was discovered from a telescope on Earth in 1978; the four smaller ones were spotted in the last decade by the Hubble Space Telescope, which is in orbit around Earth.

The team working on New Horizons, which will fly by Pluto on Tuesday, has assiduously searched for additional moons and so far has found none. That is both a relief — moons and smaller debris are potential dangers to a spacecraft speeding at 31,000 miles per hour — and a surprise.

"It's as clean as a whistle," said S. Alan Stern, the principal investigator for New Horizons.

"Isn’t it just amazingly coincidental to you," Dr. Stern said, "like it is to me and others here, that we were just barely able to see the smallest satellite from Earth and there was nothing else?"

The telescopic camera on New Horizons can already spot objects as small as a mile across, and it will be even more eagle-eyed as it approaches.

Dr. Kenyon, who is not on the New Horizons team, has a second prediction about Pluto: "It will have a lot of craters."

That is not going out on a limb. Stuff runs into everything in the solar system, and Pluto is unlikely to have any geological processes that could erase impact craters like a shaken Etch-a-Sketch.

Tune in in the next few days to find out what reality has revealed.—KENNETH CHANG

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Pluto, seen here in a composite image from July 11 with its moon Charon, is now known to be bigger than Eris, another dwarf planet. Credit
NASA/JHUAPL/SWRI

One of the early science results from NASA's New Horizons mission: a definitive measurement of Pluto's girth.

Pluto is 1,472 miles wide, give or take six miles.

That is a lot more precise than earlier estimates of the diameter, which had ranged from 1,428 miles to 1,490 miles.

"That settles the debate about the largest object in the Kuiper belt," said S. Alan Stern, the mission's principal investigator, referring to the ring of icy debris beyond Neptune's orbit.

Pluto is now known to be bigger than Eris, the icy world discovered farther out in the Kuiper belt in 2005. Eris was so bright that it seemed certain to be bigger than Pluto, and initial measurements seemed to confirm that.

But later, astronomers were able to make a more precise measurement when a star passed behind Eris. Eris was just 1,453 miles in diameter.

Similar measurements had been made for Pluto, but the uncertainties were greater, because Pluto has an atmosphere that bends starlight.

The New Horizons scientists used different techniques to measure Pluto's diameter.

The larger diameter, in turn, means that Pluto is less dense than had been thought, and that in turn means a greater proportion of ice and less rock in its composition.

And while Pluto is now the biggest object in the Kuiper belt, Eris remains the heavyweight: It is 27 percent more massive than Pluto.—KENNETH CHANG

Q. Why does Morton’s toe seem like the rule and not the exception during sandal season?

A. Morton’s toe, in which the second toe is longer than the big toe, has a broad range of reported prevalence, from less than 3 percent to nearly a third of the general population and as much as 90 percent of some isolated populations. It is believed to be an inherited characteristic, but may not follow a simple dominant-recessive pattern.

One speculative explanation for seeing Morton’s toe show up in revealing shoes in summer is an aesthetic preference for showing off such a foot design, one apparently shared by makers of Greek statuary and the sandaled Statue of Liberty.

Morton’s toe was first described as a medical condition in a 1927 article by Dudley Joy Morton, an orthopedic surgeon, in The Journal of Bone and Joint Surgery. It is not so much that the second toe is too long, but that the first metatarsal bone, which connects the big toe to the main part of the foot, is too short.

The condition can shift too much the weight to the second metatarsal, causing pain, callus formation and musculoskeletal problems. Surgical correction is sometimes used, but proper foot support is the treatment of first resort.—C. CLAIBORNE RAY

Send your questions to C. Claiborne Ray at questions@nytimes.com. Questions of general interest will be answered, but requests for medical advice cannot be honored and unpublished letters cannot be answered individually.

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“When you open the newspaper, it doesn’t usually say ‘Paleontologist wanted.’ There are only a few jobs like this in your lifetime that you might be qualified for. This is my dream job.”

"Everything is going great," Glen Fountain, the mission's project manager, said on Sunday.

Here's what to expect when you're expecting Pluto:

The spacecraft is on target, so the mission team has passed on making any small corrections to the trajectory or the computer programming for the encounter.

At 11:17 p.m. Monday, the mission control at Johns Hopkins Applied Physics Laboratory in Maryland will receive the last update from the spacecraft before the flyby begins. The spacecraft then begins 22 hours of complicated choreography for its observations as it speeds toward Pluto at 30,800 miles per hour. Because of the spacecraft's design, it cannot collect data and talk to Earth at the same time.

Around 7:50 a.m. Eastern time on Tuesday, give or take a minute or so, it will zip 7,800 miles above Pluto's surface, providing an extraordinary close-up first look. The clearest photos of the surface will have a resolution of about 75 yards per pixel. NASA TV will provide coverage beginning at 7:30 a.m.

At the time of the flyby, no one on Earth will know the fate of New Horizons and whether it is accomplishing its tasks. Around 4:30 p.m. the spacecraft will turn its antenna back toward Earth to send a brief "Hi, I'm still alive" message.

Because light takes 4.5 hours to travel the three billion miles from Pluto to Earth, the status message will not arrive at mission control until 8:53 p.m Tuesday. The transmission, which is to last until 9:09, is to provide a quick summary of how the day went. That is to be the first communication from the spacecraft in 22 hours. It will not include any photographs. NASA TV coverage will begin at 8:30 p.m.

NASA will hold a news conference at 9:30 p.m.

On Wednesday, with the flyby complete, the spacecraft will begin sending back images and other data. The highlights are to be revealed at a 3 p.m. news conference. But that will be only the tip of the iceberg. It will take until late 2016 for all of the data on New Horizons to be received back on Earth.—KENNETH CHANG

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To get to Pluto, take a left at Jupiter. The New Horizons spacecraft, launched in 2006, used a gravitational slingshot boost from Jupiter to speed its way.Credit
Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Nine and a half years and three billion miles later, NASA's New Horizons spacecraft will zoom past Pluto on Tuesday. And mission managers are confident that they have aimed precisely enough that the spacecraft, traveling 31,000 miles an hour, will pass through a rectangle just 60 miles by 90 miles at its closest approach to Pluto.

In terms of accuracy, that's like driving from New York to San Francisco and ending up within about five inches of the parking spot you had selected before setting out.

A computer program calculated the necessary trajectory, including a swing by Jupiter to pick up velocity. That process is essentially unchanged from decades ago, when the Pioneer and Voyager probes similarly navigated to the outer solar system.

The essential equation is simply F=ma, Newton's Second Law, where F is the sum of all the forces.

Nonetheless, the details matter. "We used to lob spacecraft at the moon and miss," said Mark Holdridge, the mission manager for the Pluto encounter. "It's very easy to make a mistake."

The calculations have to factor in the gravitational tug of the sun and the planets. The tiny thrusters that spin New Horizons around also knock it off course slightly. Even the heat from the chunk of plutonium that acts as the spacecraft's battery produces a smidgen of thrust, and so does the small pressure of sunlight hitting the spacecraft. All must be taken into account.

Two teams of navigators do the calculations independently and then compare and reconcile their answers. That avoids mistakes like the one in 1999 when a mix-up between metric and imperial units pushed NASA's Mars Climate Orbiter slightly off course. It dipped too far into the atmosphere as it was entering orbit and was torn apart.

The calculations are not perfect, so New Horizons has also fired its thrusters nine times during the nine and a half years for small course corrections, most recently two weeks ago.

For the 11 million miles since then, New Horizons has been coasting, aimed at the middle of that 60-by-90-mile rectangle.

An earlier version of this post misstated the accuracy with which a driver could get a car from New York to a particular parking space in San Francisco, if it were as accurate as the New Horizons flight calculations. It is within about five inches, not five feet.

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NASA's New Horizons spacecraft took this picture of Pluto early on Saturday.Credit
NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

The scientists working on NASA's New Horizons mission had called them "brass knuckles" — a series of four dark spots on the surface of Pluto, each about the size of Missouri, about 300 miles wide.

As New Horizons speeds closer, the picture gets clearer. From 2.5 million miles out, the spots appear to have complex and irregular boundaries between the bright and dark regions.

But this is probably the last good look at these particular spots, which are near the dwarf planet's equator. (In the photograph, they are seen at the bottom in the photograph, because Pluto's axis of rotation is tipped over, with the north pole facing the sun and the approaching spacecraft. From this perspective, essentially looking down at a spinning top, the north pole is in the brighter region in the upper center part of the picture.)

Pluto rotates every 6.4 days, so when New Horizons is closest to it, on Tuesday, this part of the dark belt will have rotated into darkness.

But that just means there will be new surprises as more of the landscape comes into view.— KENNETH CHANG

The theory of evolution and a schoolteacher named John T. Scopes went before a jury in the small town of Dayton, Tenn., 90 years ago Friday. Sometimes referred to as the “true trial of the century,” it attracted such interest that at one point the town contemplated moving it to a baseball field with a capacity to seat 20,000 people.

The trial actually began as a public relations stunt. In 1925, the American Civil Liberties Union took out an ad in a Chattanooga newspaper seeking a test case to challenge the Butler Act, a Tennessee law that forbade the teaching of any account of creation that differed from biblical tellings. Residents of Dayton saw the ad and believed that finding someone to test the law would bring attention to their town. Mr. Scopes, who had strong convictions around freedom of discussion in the classroom, agreed to challenge the law.

Many elements of the trial had a carnival-like atmosphere, including the appearance in Dayton of out-of-towners with chimpanzees and a 3-and-a-half foot man who was called a "missing link." They were put on display for jurors and the animals' owners argued that this was proof that primates had descended from humans after a period of degradation.

Early accounts of Mr. Scopes referred to him as "professor," but in reality he was a couple of years out of college and hired in Dayton to coach athletics in addition to teaching, and was not a specialist in biology. Mr. Scopes presented himself as a Christian who believed that the theory of evolution squared with his faith.

The trial did little to settle any scientific or theological questions. The Scopes defense, led by Clarence Darrow, had a group of scientists on hand. But the judge ruled a week into the trial that their testimony was not needed because the question before the court was only whether Mr. Scopes had given his students a lesson on evolution, a fact he did not contest, not whether evolution was true.

Mr. Scopes was convicted of a misdemeanor and fined $100. But the trial offered a major public forum for the clash of science and religion. Or as Mr. Darrow put it, the trial was, "the first of this sort since we stopped trying people in America for witchcraft."

Mr. Scopes, who died in 1970, outlived the law he was convicted of violating. (It was overturned in 1967.) But the fight about the teaching of evolution and creationism in American schools persists.—MICHAEL ROSTON

An earlier version of this post misstated the year in which the Butler Act, a law forbidding the teaching of evolution, was passed in Tennessee. It was 1925, not 1920.

In the 13 minutes it will take you to watch the video above, NASA’s New Horizons spacecraft could get from New York to Kenya, India or China. It is moving that fast. And on the morning of Tuesday, July 14, after nine and a half years hurtling forward at 31,000 miles per hour, it will pass Pluto.

If you want to understand how the mission came to be and why it is such a big deal, we recommend sitting down with a cup of tea or glass of wine and watching this documentary. Here are a few quotes you may want to keep in reserve for conversation lulls at future summer barbecues:

NASA planners are counting on Pluto’s moon, Charon, to clear away debris that could do severe damage to New Horizons.

“If the spacecraft were hit by something even the size of a rice pellet, it could pierce into the spacecraft, and potentially cause it to stop functioning. It would be like colliding with a brick at 60 miles an hour.”—Dr. Stern

New Horizons will only get one shot at studying Pluto.

"So the key defining characteristic of this mission is that it’s one shot, you know, one flyby. It’s very fast, it had to be fast to get there in a reasonable amount of time. And so we want everything to go flawlessly, right, the first time. The only time. "—Mark Holdridge, New Horizons Encounter Mission Manager

New Horizons fast is a whole other level of fast:

“It took the Apollo astronauts three days to get to the moon. The New Horizon spacecraft passed the moon in nine hours.”—Carter Emmart, Director of Astrovisualization, American Museum of Natural History

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“The amoral status of an algorithm does not negate its effects on society.”

—

Amit Datta and Anupam Datta of Carnegie Mellon and Michael Carl Tschantz of the International Computer Science Institute, authors of a study that found a Google advertisement favored men over women.

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“At least some times, more brains are better than one.”

—

Karen S. Rommelfanger, director of the Neuroethics Program at the Center for Ethics at Emory University on studies of brain networking involving monkeys and rats.

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In Hawaii, box jellies have a rectangular body, or bell, of about three inches long and four red-tipped tentacles. It is easy to miss the otherwise clear creatures in the water. A nerve ring coordinates pulsing in the top of the box jelly’s bell and sends it forward at speeds of around three to five miles per hour. Credit
Dr. Angel Yanagihara and Dr. Eric Rottinger/University of Hawaii Manoa

Like clockwork, eight to 10 days after a full moon, a swarm of toxic box jellyfish appear in the shallows of some of the world’s most beautiful waters. This is the week of their sting-filled arrival. From Thursday through Saturday, bathers along Waikiki Beach in Hawaii, Swan River in Western Australia and parts of Guam, the Caribbean and the Great Barrier Reef may want to avoid the nearly transparent creatures.

Blooms of thousands of species of jellyfish (not just box jellies) occur all over the world throughout the year. But the swarms of the Alatina alata, as it's known, are distinctive, said Dr. Angel Yanagihara, a biochemist and box jelly researcher at The University of Hawaii at Manoa, because of how predictably their reproductive patterns follow the moon. Every month, at the same time, hundreds to thousands fill the coastal waters. A swarm or bloom, as it is also called, lasts about three days, as they spawn.

“After which, they appear to all die,” she said. The Waikiki Aquarium maintains a jellyfish bloom calendar for planning purposes.

Box jellies, like coral, anemone and other jellyfish, are armed with cells that can be injected like venom harpoons into prey or predators. Human movement can trigger the jellies’ sensors to fire.

Although it is uncommon, the stings of Alatina alata sometimes accompany severe symptoms that can send their victims to the hospital. Barring special creams, the best way to treat a sting, Dr. Yanagihara said, is to spray it with vinegar and then immerse it in hot water.

This particular box jelly is not to be confused with the basketball-size Australian Box Jelly (Chironex fleckeri), which is often referred to as the ocean’s most venomous animal. But, Dr. Yanagihara said these box jellies are like hot peppers — even small ones can pack a big punch.—JOANNA KLEIN

The exhibit here almost created a young math hero earlier this summer. During a visit to Boston's Museum of Science, 15-year-old Joseph Rosenfeld uncovered what seemed to be an error in a math equation that had stood unquestioned on the wall for 34 years.

The exhibit aimed to explain a mathematical formula known as the "golden ratio," which describes a specific relationship between a line, shape or object and its parts. The museum explained the formula in terms of the short side (BC) of a line being divided by the long side (AB) of the line:

Mr. Rosenfeld said that the museum had mixed up its positive signs with negative signs. The museum conceded to Mr. Rosenfeld's keen eye and then the Internet went wild — only for the museum to reverse course, asserting that the exhibit was correct.

How did all of this confusion occur? Because there's more than one way to write the ratio.

“The equation that is written in the museum is for 1 over the golden ratio,” explained astrophysicist Mario Livio who wrote the book, "The Golden Ratio." This expression is commonly known as the reciprocal of the golden ratio. The more common way of seeing the golden ratio portrayed is in terms of the long side (AB) being divided by the short side (BC):

In March NASA’s Opportunity rover completed the first-ever Martian marathon, traversing 26.2 miles across the dusty red planet.

Opportunity's camera has captured footage from every mile crossed over the 11 year journey. Now NASA has released an 8-minute time-lapse of the rover's entire expedition. We then condensed the 26-mile journey further into just 26 seconds. The video lets us drive with Opportunity as it treks through Mars’ Endurance Crater, across the Victoria Crater and finally arrives at Endeavour Crater. Next Stop: the western end of the appropriately named Marathon Valley.—NICHOLAS ST. FLEUR

We've been tracking the Curiosity rover's journey across Mars as well. See photos and take a hike across Gale Crater.

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“Think about it: About a billion years ago, we had a common ancestor, and it began to diverge into two species, and one of them, a billion years later, ended up being a cotton plant and the other ended up being us!”

“I said we would find a Pluto that was two words: something wonderful. It’s turning out to be completely true.”

—

Alan Stern, principal investigator of NASA's New Horizons mission, on his only prediction he made about the Pluto mission and what it would discover.

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These illustrations were created from scans of real people by New York City based startup Body Labs, which creates 3-D body models to help companies create clothing and other wearable products that fit just right. For each person the number labeled V is their body's volume, or the amount of fluid that would fill a container the same size as their body, in liters.Credit
BodyLabs

The illustrations here were created from scans of six people, who were all 5 feet 9 inches tall and 172 pounds. This means that though their bodies look very different, they all have exactly the same body mass index, or B.M.I. At 25.4, technically each of them could be considered overweight. (By the most common definition people with a B.M.I. over 25 are overweight and those with a B.M.I. over 30 are considered obese.)

How is it possible that the same B.M.I. can look so different? The simple explanation is that muscle and bone are denser than fat and some people carry more or less weight in their torso or legs. As B.M.I. factors in only height and weight, it sidesteps these differences.

This is a crucial shortcoming as some research now suggests that body fat percentage and body composition are more important indicators of health than weight alone. That puts the emphasis on exercises that don't just burn calories, but also build muscle. This also means that, to get a summer "beach body," a strict weight loss goal might not be the right path.—ALBERT SUN

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Pluto in color, captured on July 3 by New Horizons' Long Range Reconnaissance Imager with data from the Ralph Instrument.Credit
NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

This image of Pluto, released Monday afternoon by NASA, is the crispest ever taken. But it is nothing compared with what you will see in a week, when NASA's New Horizons spacecraft buzzes just 7,800 miles above Pluto's surface.

This visit will bring the dwarf planet into focus for the first time, illuminating mysterious dark regions on its surface and possibly erupting ice volcanoes. By photographing a surface from multiple vantage points, scientists will be able to construct a topographic map of the former ninth planet.

Those working on this mission have been waiting many years for a close-up. The fly-by, at 7:50 a.m. Eastern time on July 14, comes 14 years after the initial proposal and nine and a half years after New Horizons left Earth. The spacecraft will fly through the Pluto system at about 10 miles per second or around 31,000 miles per hour.—KENNETH CHANG

Solar Impulse 2, an experimental plane flown by pilots who aim to complete the first round-the-world solar-powered flight, landed in Hawaii on Friday after five days aloft.

The pilots are Andre Borschberg and Bertrand Piccard, Swiss explorers who hope to draw attention to the capabilities of clean technologies and renewable energy. Mr. Borschberg was at the helm for this leg of the flight — more than 4,000 miles from Nagoya, Japan, to Oahu — which set a record as the world's longest solar-powered flight by both time and distance, and as the longest solo flight by time.

The aircraft, which has 17,000 solar cells and a wingspan of 236 feet, began the mission on March 9 in Abu Dhabi. All told, the trip is expected to cover almost 22,000 miles.

Be jealous, collectors of frequent-flier miles.—JILL TAYLOR

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“In the very unlikely event a shark does bite, the best thing to do is fight back. Grab at the eyes and gills, which are very sensitive. Punching the shark in the nose may help but is difficult to do in the water.”

New York Times food writers have advocated cooking directly on hot coals this Fourth of July, but the truly adventurous may want to consider another approach: lava-grilled steak.

The Syracuse University professors Bob Wysocki and Jeff Karson, the leaders of this minimalist technique, say the key is to start with thin-cut steaks, the more marbled the better.

You then find the nearest retrofitted bronze furnace. (Very likely, that is the one the professors have built for themselves in Syracuse as part of the university’s Lava Project. When not cooking dinner with it, Mr. Wysocki, an artist, and Mr. Karson, a geologist, create lava for scientific research and sculptures.)

Here’s their recipe:

Preheat the furnace to 2,500 degrees Fahrenheit.(“It takes a good 24 hours to heat the furnace up,” Mr. Wysocki said.)

Add 800 pounds of Wisconsin basaltic gravel in 75-pound batches.

Cook for 24 hours.

While the lava is cooking, prepare a trough and set your grill over it.

Once the lava is thick and smooth, pour it through your trough.

If you’re using one-inch or thicker steaks, allow the lava’s rising heat to cook them for one minute per side and then pull them off the grill.

Enjoy.

Variations:

If you’re using 1/2" to 3/4" cuts, sear them for 30 seconds per side and then “rest the steak as soon as you char it, so you trap in all of the fat and juices,” Mr. Wysocki said.

For an “unctuous” medium rare steak, Mr. Wysocki recommends waiting about five minutes until the lava “cools down” to 1,000 degrees Fahrenheit (from 2,000 degrees). Then return the steak to the grill for three to four minutes a side.

Alternatively, wait until the molten lava hardens into what looks like dirty glass and you can drop the steaks directly on it.

Flames and smoke will dance around the steaks as they sizzle, but the professors say the steaks are safe to eat because their basic basaltic ingredients don't release any volatile compounds when melted.

You might take inspiration from NPR's Adam Cole, who made a delightful video about the Syracuse caldron, and follow with a dessert of lava-toasted marshmallow.—EMILY HAGER

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A stained skeleton of a seahorse and a model of its tail, which comprises square prisms surrounded by bony plates.Credit
Dominique Adriaens/Ghent University and Michael Porter/Clemson University

Living things are often roundish, sometimes sharp and pointy, but rarely square. But the seahorse, in both its geometry and other traits, is an exception.

They are fish, but they don’t look like fish. They have a hard, bony external skeleton. The male endures pregnancy and birth (contractions may last 12 hours), and their prehensile tail, which they use to hang on to things, is square.

Michael M. Porter, at Clemson University, is a mechanical engineer, which made him wonder about the mechanics of the tail. Why square?

He and some other scientists made 3-D printed models of the tail — no seahorses were tormented during this research — and found, as he reported in Science, that the square tail grips better, is more sturdy and bounces back into shape more quickly than round tails do from torsion, meaning being twisted around and generally messed with.

So why aren’t all prehensile tails square? Evolution doesn’t just pick good ideas out of thin air; it refines what already exists. Probably, he said, the square structure appeared first in something like a pipefish, and then turned out to be useful in other ways.

And, there just aren’t a lot of square ancestors out there — geometrically speaking, that is.—JAMES GORMAN

We welcome your feedback and thoughts on how to best experience science in the summer. You can send us an email at summerofscience@nytimes.com or tag your Instagram photos #nytscience.

The correct answer is A.“Depending on the sediment type, you put different shoes on the spider.”

That scientifically revealing mud is better known as sediment and this spiderlike apparatus is called a multi-corer. Unwieldy as it might look, the instrument performs a fairly delicate task. Without disturbing its surroundings, it gently plunges several tubes into the ocean floor to extract stratified samples of sediment.

For oceanographers, sediment represents a revealing trove of clues into Earth’s history. Some coring devices slam into the ocean floor with enough force to extract samples up to 20 meters tall — large enough to take researchers millions of years back in the sedimentary record.

The multi-corer here prizes smaller samples, in better condition, for a more precise look at the recent history of the seafloor. To achieve this, even the moment of touchdown is engineered for minimum impact.—LOUIS LUCERO II

For the past week, Jupiter and Venus have been drawing closer in their race around the sun. On Tuesday night they nearly kissed. Planet-gazers from around the world documented the celestial dance and posted an array of photos of the #venusjupiterconjuction. These were some of our favorites, from both Monday and Tuesday, that people shared with us using the tag #nytscience. The locations represented here are New South Wales, Australia; Yamdrok Lake, Tibet; Fort Lauderdale, Fla.; Chiang Mai, Thailand; American Canyon and Los Angeles; Key Biscayne and St. Petersburg, Fla.

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“People sometimes say if lights made the same noise as dripping water, more people would shut their lights off.”

Silent for 33 years, Wolf volcano in the Galapagos Islands released an explosive howl a few weeks ago, spewing fire and ash nearly 50,000 feet high, according to NASA.

On Tuesday the agency released images captured by its Terra satellite on June 11 that show lava leaking across Isabela Island and into the sea.

To better display the aftermath of the eruption, NASA digitally altered the image so that the volcanic spew looks like black rivers flooding red areas, which represent the island's grass and other plants.—NICHOLAS ST. FLEUR

By now you may have heard a joke or two about what someone wants to do with the extra time tonight. Computer clocks will count an additional second Tuesday night, known as a leap second, to offset a lag in the Earth’s rotation.

But while the added time may not seem like much to a person — who could squander a second with almost three blinks of an eye — for a fast-paced creature like the hummingbird, that spare moment could mean as many as 80 extra wing flaps as it zooms from flower to flower drinking nectar.

—NICHOLAS ST. FLEUR

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A headline and graphic from Page 50 of a May 30, 1965, Times article about the Tunguska blast. The supposed “antirock” was antimatter.

As though “Deep Impact” or “Armageddon” was not enough, a German filmmaker has declared today Asteroid Day as a way to raise awareness about the prospect of a rock from space ending civilization as we know it. Why choose June 30 for this drive for investing in planetary defenses against asteroid strikes?

One word: Tunguska.

On June 30, 1908, a hydrogen-bomb-level explosion occurred over a remote section of Siberia, demolishing tens of millions of trees over hundreds of square miles.

In contrast, a 1929 article in The Times, the first time it was mentioned here, offered a much more down-to-earth description of the explosion. Scientists had completed very little study of the blast’s leftovers at that time, and the article described the event as the moment when “an enormous mass of meteoric material came to earth in the wilds of Siberia.”

Pseudo-holidays aside, protecting the planet from objects from outer space is an actual pursuit, involving policy makers and scientists. Recently the National Nuclear Security Administration and NASA agreed to cooperate on planetary defense.

The demise of SpaceX's Falcon 9 rocket less than three minutes after its launch on Sunday certainly looked a lot like an explosion.

But the reason that The New York Times articles on the event do not currently contain the word “explode” has to do with combustion. An explosion, at least technically, is a rapid combustion where gases expand outward. But at about 28 miles up, there is much less oxygen in the air to combust, so it is unlikely the rocket actually exploded.

SpaceX is still investigating precisely what happened, but Elon Musk said on Sunday that the problem appeared to be too much pressure in the liquid oxygen tank of the second stage. At some point, the rocket's structure failed, and then the air resistance — the rocket was traveling at 3,100 miles per hour — tore it apart. Thus, it is more accurately described as a breaking up, disassembling or disintegrating rather than exploding.

Perhaps you can file this away as an example of a clash between technical precision and Google search. A number of the stories about SpaceX that are currently ranking high on Google News include the word explode or explosion.

—KENNETH CHANG

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A fisherman was hidden in this diagram in a paper titled, "The Photosynthetic Cycle: CO2Dependent Transients."Credit
Journal of the American Chemical Society

Sometimes a particularly close reading of a scientific paper is rewarded with a tiny buried surprise.

Earlier this month, one of our readers, Stephen A. Silver, pointed out that in an article published in Current Biology, Caleb M. Brown, a palaeontologist at the Royal Tyrrell Museum, wrote he would “like to highlight the ongoing and unwavering support of Lorna O’Brien. Lorna, will you marry me?” She apparently said yes.

Dr. Brown was participating in a long tradition of burying Easter eggs in journal articles.

Back in 1955, a diagram in a paper on photosynthesis included a tiny man fishing in one of the reactors. According to the Royal Society of Chemistry, the author of the paper, Nobel-prize winning chemist Melvin Calvin, who died in 1997, never realized that one of his graduate students had snuck the little fisherman into the drawing to win a bet.

In 2009, Biyu J. He, a neuroscientist, left a political Easter egg in the acknowledgements section of an article : “B.J.H. would also like to thank the U.S. Immigration Service under the Bush administration, whose visa background security check forced her to spend two months … free of routine obligations — it was during this time that the hypothesis presented herein was initially conjectured.”

On Sunday, a Falcon 9 rocket disintegrated on its way to the International Space Station, the first failure in 19 launches.

Early Monday morning, Elon Musk, the chief executive of SpaceX, tweeted an update about the loss:

"Cause still unknown after several thousand engineering-hours of review. Now parsing data with a hex editor to recover final milliseconds." —@ElonMusk

Since this was 17 hours after the accident, and one engineer would have put in 17 engineering-hours, Mr. Musk's statement about "several thousand engineering-hours" is a geeky way of telling us there are hundreds of people at SpaceX on the case.

A hex editor, for those who are not familiar, is a computer program that helps navigate the 1s and 0s that are the language of digital machines. The hex part does not refer to magic spells, but rather a shortening of the word, hexadecimal. (Our everyday counting system, based on our 10 fingers is called base-10, whereas this system uses base-16.)

Presumably, as the rocket fell to pieces, the data being sent down became garbled. The hex editor allows them to take a closer look and try to unscramble the bits.

Humans are not good at gleaning meaning from something like:

10110111000110101110110101101101101101110111

especially if there are millions of 1s and 0s. So computer programmers sometimes break that down into groups of four:

1011 0111 0001 1010 1110 1101 0110 1101 1011 0111 0111

And then replace each group of 4 with a digit or letter. It's like a secret code:

0000 = 0

0001 = 1

0010 = 2

0011 = 3

0100 = 4

0101 = 5

0110 = 6

0111 = 7

1000 = 8

1001 = 9

1010 = A

1011 = B

1100 = C

1101 = D

1110 = E

1111 = F

That simplifies the 1s and 0s to something a bit more readable:

B71AED6DB77

Somewhere within these strings of data engineers hope to find a clue to the rocket's failure.

—KENNETH CHANG

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Just as the sun had set over Szubin, Poland, a photographer captured this conjunction of Jupiter, left, and Venus, right, in March 2012. His daughter Nicola extended her arms as if to touch the planets, which will appear closer in this year’s conjunction. Credit
Marek Nikodem/Polish Amateur Astronomy Society

Over the past week, you may have noticed what appear to be two superbright stars near the horizon. Those aren’t stars; they’re planets in a celestial race around the sun. On Tuesday, Venus will come neck-and-neck with Jupiter.

That day, at 2:17 pm Universal Time or 10:17 am E.T., the two planets will be at their closest. You can see this unusual sight, known as a conjunction, from just about anywhere in the world.

The optimal viewing location, according to Jackie Faherty, an astrophysicist at the American Museum of Natural History in New York, is one where where the sun sets just as the planets approach one another. Complete darkness is not necessary to see these bright objects, but it helps.

Regardless of where you are, your viewing instructions are simple: At sunset, get away from buildings or trees that might block your view of the western sky. Stick an arm out, give a thumbs up, and squint your eyes. Venus and Jupiter should be about one third of a degree, or about a thumb’s width, apart.

The following night the planets should be visible as well — their positions will just be slightly different.

"You’re not going to watch them speed past; it’s a slow-moving process," said Dr. Faherty.

Slow in this case means that Jupiter is moving at around eight miles a second, while Venus is moving about 22 miles a second.

—JOANNA KLEIN

We welcome your feedback and thoughts on how to best experience science in the summer. You can send us an email at summerofscience@nytimes.com or tag your Instagram photos #nytscience.

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“A gallon of water is pennies. It’s the loss that’s the tragedy.”

—

Joe Castruita, the former director of water distribution for the Los Angeles Department of Water and Power on water pipe leaks.

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A headline from page 22 of a Nov. 11, 1925, edition of The New York Times. On June 23, 1926, the test was given out for the first time.

“If a package containing twenty cigarettes costs fifteen cents, how many cigarettes can be bought for ninety cents?” was one of the questions.

From the start, the test did not receive great reviews. When Yale announced its freshman class in September 1926, members of which had taken the exam, a Times article included a sub-headline noting that the SAT was, “Not as Valuable as It Was Thought to Be,” and that the test did not seem to offer any tools for separating out students who appeared equally-qualified by other measurements. But by February 1927, the Yale admissions department had apparently come around, and all applicants were required to take the SAT.

Why require students to take a standardized test? In the 1920s, American colleges and universities were faced with a flood of applicants, and selecting who should and should not make it to campus was increasingly difficult. To decide who was fit to attend college, members of what is now known as the College Board proposed adapting intelligence testing methods they first saw used during World War I. They faced opposition to this approach, and Nicholas Butler, president of Columbia University, said in 1925 that, “It took ten or fifteen years to shell out all the occupants from their bombproof entrenchments.”—MICHAEL ROSTON

Anyone who fishes for largemouth bass knows that they suck in prey. But scientists at Brown University wanted to know what muscles old bucket mouth uses to quickly double the volume of its mouth and vacuum in a meal.

Experiments with bass and goldfish, X-ray video analysis and calculations of how much power was needed to open that big mouth so fast, showed that body muscles, not head ones, provided up to 95 percent of the power.

Many other fish feed this way, the researchers noted, no doubt also using the same muscles for swimming and feeding, an impressive feat of coordination.—JAMES GORMAN

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In this video, elephants appear to be dancing to a rumba. They did not react to the tango.Credit
Pairi Diaza Zoo

These elephants at the Pairi Diaza Zoo in Belgium recently received a personal concert from a string quintet, but were hard to impress.

“When they played the tango, they walked off,” said Dr. Tim Bouts, the Paira Diaza’s zoological director. “Then they played the rumba and they all came back.”

Elephants are acoustically sensitive animals and can hear a much greater range of sound than humans, from deep in the infra-sound spectrum to higher frequencies like what humans hear.

Dr. Bouts' hypothesis is that the elephants preferred the deeper vibrations in the rumba, when the double bass and cello had bigger parts, to the tango, when the high-pitched violins dominated.

Throughout the concert, the elephants occasionally pricked up their ears, appeared to sway to the music and lifted their trunks as if mimicking the quintet’s bows. During a lullaby, the 33-year-old grandmother of the herd nearly drifted off to sleep.

Conclusions, of course, cannot be drawn from this one performance, but Dr. Bouts is planning a study that will try to establish whether the elephants respond differently to various types of music. Conveniently, his wife is a member of the quintet, so it should make for some charming evenings in the zoo’s elephant temple.– EMILY B. HAGER

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A tiger trying to keep cool at the Karachi Zoo on Wednesday.Credit
Shahzaib Akber/European Pressphoto Agency

Though this Bengal Tiger may look cute, this is actually a portrait of distress. Pakistan has been hit by the worst heat wave in more than a decade, with temperatures reaching 113 degrees Fahrenheit this week.

The heat has killed more than 800 people and sent 8,000 to the hospital since Sunday.

The soaring temperatures may have broken with the cooling arrival of winds and rain on Wednesday, according to The Associated Press.

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A computer rendering of how the ancient Hallucigenia may have walked. Scientists had mistakenly identified a glob of fossilized liquid found on the other end as the worm's head.Credit
Lars Fields

Hallucigenia was a spiny, wormlike creature that squirmed across the sea floor some 500 million years ago. But for decades, researchers could not make heads or tails of its bizarre fossilized remains, only now discovering which end held its head.

On Wednesday — after years of misidentifying a glob of fossilized liquid from the worm's gut as its head — a team of researchers used a high-tech microscope to uncover the creature's eyes and toothy "smile."—NICHOLAS ST. FLEUR

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Commander Scott Kelly's view from the International Space Station on Tuesday. Credit
NASA/Reuters

The storm’s effects lit up our planet’s skies with aurora, visible across the world. (The tag Northern Lights on Instagram reveals an array of colorful light displays.) And if you were lucky enough to be aboard the International Space Station, like NASA astronaut Commander Scott Kelly, you would have witnessed a scene like the one in the photo above.

Strong solar blasts could cause some geomagnetic storm activity again this evening. If you're far enough north and in a dark enough place, you could possibly see some dancing lights in the sky.—MICHAEL ROSTON

Earlier this week medical researchers in Australia reported a case where a woman arrived at their hospital having suffered nerve damage after squatting for an extended period of time while wearing skinny jeans.

“The chance of ending up in the hospital from wearing your skinny jeans is like the chance of getting hit by lightning or winning the lottery,” said Dr. Natalie Evans, a vascular medicine specialist at the Cleveland Clinic.

“This was more of a freak accident, it sounds like to me,” she said, adding that although the woman's tight pants may have exacerbated the muscle damage that she suffered from squatting, which caused her to pinch a nerve, for the most part skinny jeans pose few health risks from a nerve and vascular point of view.—NICHOLAS ST. FLEUR

Eighty-five years after a young astronomer, Clyde Tombaugh, discerned it as a dot of light moving through the stars, scientists are preparing to get their first close-up photograph of the planet and its five moons. On July 14, the New Horizons spacecraft will fly by Pluto, on its way into the wild black yonder.

Also coming into view is Pluto's biggest moon, Charon. The pair dance around their common center of gravity, forming what astronomers call a double planet. Both of them are tiny worlds of rock and ice.

Earlier this week, from a distance of some 20 million miles New Horizons glimpsed a mysterious dark spot on Charon's pole that scientists referred to as an "anti-polar cap." Planet experts are used to seeing bright spots caused by frost at a planet or moon's poles, but not dark stuff.

"Who ordered that?" asked Alan Stern of the Southwest Research Institute and leader of the New Horizons mission, echoing a famous phrase by which the physicist Isidor Rabi once responded to the discovery of a new unexpected subatomic particle.—DENNIS OVERBYE

An artist's impression showing GJ 436b at the beginning of its transit across the surface of its parent star, a red dwarf that is half the diameter of our sun.Credit
D.Ehrenreich and V. Bourrier/Université de Genève; A. Gracia Berná, via Universität Bern

A planet outside of our solar system is losing its atmosphere, which is dissipating into a giant cloud, according to a new study.

GJ 436b is so close to its parent star — 33 times as close as the Earth is to the sun — that its atmosphere is evaporating, creating a large cloud around the planet, said David Ehrenreich, an astrophysicist at the University of Geneva and one of the study’s authors.

“What we see is the planet kind of turning into an enormous monster much bigger than its star,” Dr. Ehrenreich said.

The star is much fainter than our sun, and the evaporating gases are not swept away. Instead, the star “allows the huge cloud to gather,” Dr. Ehrenreich said. He and his colleagues report their findings in the current issue of the journal Nature.

The researchers analyzed ultraviolet observations of the Neptune-mass exoplanet, located 33 light years from Earth. The planet orbits a small red dwarf star in the constellation Leo.

As the planet loses mass, the cloud of hydrogen atoms continues to grow. Stellar radiation has given the cloud a long tail — nine million miles in length — trailing the planet.

“It has always been a mystery how these rocky planets so close to their stars could form,” Dr. Ehrenreich said. “One possibility is that they are the remnants that have lost mass because of atmospheric evaporation.”—SINDYA N. BHANOO

Lovebirds can rotate their heads up to 2,700 degrees per second, researchers report in the journal PLOS One. The speedy rotations allow for improved sight and reduced blur as they fly through dense forest environments. After recording the birds in high-speed videos, researchers at Stanford University and elsewhere found that lovebirds turn their heads precisely at the moment their wings cover their eyes, minimizing the time that their vision is obscured. The researchers hope the study will inspire camera rotation design in drones.

If you've seen the summer box office hit, “Jurassic World,’’ you know that it is a sensitive portrayal of the essence of zookeeping thinly veiled as a blockbuster action film set in a theme park of genetically engineered dinosaurs.

Or maybe you don’t. But there is little doubt that the movie has struck a chord with members of the zookeeping tribe, who have flooded the Internet with photographs of themselves reenacting a scene involving the lead actor, Chris Pratt, and the three velociraptors with whom his character shares an uneasy bond.

The character, Owen Grady, is an animal expert who has – sort of – trained the vicious dinosaurs by interacting with them. Yet as he says to one of the many humans who don't seem to really get his raptors, “It's not about control. It's a relationship based on respect."

In one memorable scene, Mr. Pratt stretches out his arms, lion-tamer-like, managing to keep them at bay so that a newbie feeder who had fallen into their cage could escape unharmed.

The homages circulating under the #JurassicZoo and #JurassicZookeeper hashtags are on one level tongue-in-cheek nods to the relative risk of handling dinosaurs famous for mauling human prey and, say, otters.

“Thanks @prattprattpratt for teaching us how to wrangle our ferocious red pandas,’’ read the caption on a picture tweeted by the Elmwood Park Zoo in Norristown, Pa., depicting a keeper striking the same pose as three reddish cuddleballs eye him quizzically.

But zookeeper enthusiasm for the meme, which blossomed first on a Facebook group for keepers, appears to be rooted in the genuine delight of seeing the under-appreciated challenge of caring for zoo animals reflected in Mr. Pratt’s balancing act.

“It’s such an iconic moment for zookeepers, when you see that character establish a connection with those animals – that’s a big part of our life,’’ said Rick Schwartz, a zookeeper at the San Diego Zoo. “You can’t just go in there and boss things around, animals don’t work that way.’’

He said he hopes that the public’s embrace of #JurassicZoo will help correct a common misconception of zookeeping as a kind of 1930s circus act, complete with whips. Or at least show people that they have a sense of humor.

For a movie that blissfully ignores the scientific consensus that dinosaurs were feathered, it may come as no surprise that the authenticity of its animal-trainer ethos ends when Mr. Pratt agrees to round up his raptors to hunt down the blood-thirsty Indominus Rex marauding through the park. “We wouldn’t go running after another animal with our animals,’’ noted Mr. Schwartz. “After that, everything is very Hollywood.’’—AMY HARMON

Mount Sinabung in Indonesia expelled lava and flames from its dome on Monday, shrouding the nearby area in smoke and ash. Officials first cautioned villagers about the volcano's eruptive activity in early June, and more than 1,200 people have evacuated their homes, according to the Associated Press.

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These two time-lapse sequences were taken in The Great Smoky Mountains National Park during the peak phase of firefly mating time.Credit
Gary Wilson/Great Smoky Mountains Association

Officially, summer has only just begun, and yet the narrow window to experience one of its great wonders is already rapidly closing.

As darkness sets over the Great Smoky Mountains in Tennessee, male fireflies hit the forest looking for mates. They blink their beaming bellies as they fly around and before long they have synchronized with their neighbors.

This bioluminescent mating dance of the rare synchronous firefly, shown above, peaks for just a few nights a year in most places.

Little slices of Georgia, West Virginia and New York have also been known to provide the right back-drop for the fleeting performance according to a survey by a group of scientists known as the Firefly International Research and Education (FIRE) team.

Making it complicated for humans, though, is the fact that there is no easy formula for figuring out where and when to watch the show. Temperature, altitude, humidity, moonlight and man-made light all play a role according to FIRE.

The light produced results from an enzymatic reaction inside all firefly larvae. Fireflies first used it as a defense mechanism. After millions of years, however, some species continued to produce light as adults, when pretty much the only thing on a firefly's agenda is sex. Most adult fireflies, including synchronous fireflies, don’t even eat. And a pair mates all night long.—JOANNA KLEIN

We welcome your feedback and thoughts on how to best experience science in the summer. You can send us an email at summerofscience@nytimes.com or tag your Instagram photos #nytscience.

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“Matter is built from a grab bag of particles whose masses differ so wildly that they appear to have been handed out by a punch-drunk God.”

On the summer solstice, the sun's warm rays bathe the Northern hemisphere longer than any other day of the year. This happens because the tilt of the Earth’s axis is at a point where it makes its deepest bow to the star.Credit
NASA

Each year on the summer solstice people flock to Stonehenge, England, to photograph the sun's rays as they dramatically peek through the stones. But some of the most intriguing solar snapshots captured on Sunday will come from a spacecraft flying a million miles away.

The Solar and Heliospheric Observatory (SOHO) is a satellite roughly the size of a pickup truck, operated by NASA and the European Space Agency, that orbits the sun and beams back clues to the fiery globe’s scorching mysteries. One of these mysteries involves the question of why certain parts of the sun burn so much hotter than others.

The 4,000-pound satellite is equipped with an ultraviolet telescope that reveals and color codes these disparities, day to day. The red side, here for example, shows a layer of the sun's surface in which material burns at about 140,000 degrees Fahrenheit. The blue side shows plasma burning in the sun's extended atmosphere, or corona, at 1.8 million degrees Fahrenheit.

The extreme differences throughout the star are not easy to explain. Why, astronomers ask, does the sun's surface burn at a relatively cool tens of thousands of degrees Fahrenheit, while the corona surrounding it burns millions of degrees hotter?

Scientists are also interested in why temperatures vary so wildly even within the corona. Jeffrey Newmark, a solar physicist at NASA, described the corona like a head of hair, with intermingling strands of grey, brown, and black — each color representing a different temperature.

“We want to understand everything about the sun," he said. "That’s the goal.” But even with the ability to identify the distinct wavelengths of light that the materials release at different temperatures, these images continue to raise more burning questions about our sun.—NICHOLAS ST. FLEUR

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A camera trap in Serengeti National Park in Tanzania captures lionesses, hyenas and jackals feasting on a zebra.Credit
SnapshotSerengeti.org

A lioness sinks its teeth into a zebra’s throat somewhere on the Serengeti plains, just a few hours before midnight.

Unbeknownst to the feasting feline, its killing blow triggers a motion-activated camera, which films the feast frame by frame. A second lioness comes into view and joins in ripping the zebra apart. Then after the two have their fill, a cackle of hyenas devours the carcass. One hyena emerges from the feeding frenzy with a dismembered zebra leg clenched in its mouth. Throughout the night, wild jackals pick at the scraps.

This is just one of many telling sequences captured by 225 camera traps set up by researchers from the University of Minnesota Lion Project. For four years, they continuously monitored wildlife across 430 square miles of Serengeti National Park in Tanzania, offering a candid glimpse of just how grisly the grasslands can be.

“I’ve spent years there and I’ve not seen half of the things that show up on these camera photos,” said Alexandra Swanson, a researcher on the project. She and her team released a selection of images earlier this month in the journal Scientific Data.

Dr. Swanson, who was a doctoral student when she began the project, set up the cameras to investigate the interactions between top predators like lions, cheetahs and hyenas.

To tackle the deluge of data from the trap cameras, she and her team helped start Snapshot Serengeti, a website that shares their images with volunteers willing to help categorize them.

More than 28,000 volunteers have combed through 1.2 million images and identified about 300,000 animals so far. But this sequence stands out according to Dr. Swanson, because no other series of images revealed such a well-attended late night feast.—NICHOLAS ST. FLEUR

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“So, more galaxies or more cells? This is not a close call. Even using the highest estimate for galaxies (200 billion) and the lowest estimate for human cells (1 trillion), there are at least 800 billion more cells in your body than there are galaxies in the known universe.”

As you celebrate your father today, consider thanking him for his full physiological commitment to your well-being. As Pam Belluck reported in September of 2011, the more a man gets involved in caring for his children, the lower his testosterone drops.

Although this prompted many a manly man to freak out at the time, it's all in the biological framing.

“The real take-home message,” said Peter Ellison, a professor of human evolutionary biology at Harvard who was not involved in the study, is that “male parental care is important. It’s important enough that it’s actually shaped the physiology of men.”

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Pyroclastic flow rolled down the slope of Mount Sinabung on June 16.Credit
Binsar Bakkara/Associated Press

For some people the interactions with nature this summer may be less welcome. Those who live at the base of the Mount Sinabung volcano in Sumatra, Indonesia, have been faced with smoke, ash and a sort of gas-filled avalanche known as pyroclastic flow over the past few weeks.

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Zooplankton collected during an expedition focused on sampling microbes from across the world’s oceans.Credit
Christian Sardet/Centre National de la Recherche Scientifique, via Tara Expéditions

This summer, during your sweaty subway ride to work or moments waiting for that ride to the lake, we invite you to hang out with us. We are going to chase fireflies, enter labs filled with peculiar instruments, and share incredible but concise tales of research gone wrong and right. School is out, but science is everywhere.

We welcome your feedback and ideas. You can email summerofscience@nytimes.com or tweet at the editor of this project, Heather Murphy @heathertal. We are also interested in seeing how you experience science in the summer. You can tag your Instagram photos #nytscience.